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Geomorphological and speleogenetical observations using terrestrial laser scanning and 3D photogrammetry in a gypsum cave (Emilia Romagna, N. Italy)

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Abstract

observations using terrestrial laser scanning and 3D photogrammetry in a gypsum cave Abstract Terrestrial Laser Scanning (TLS) and 3D photogrammetry techniques were used in a relatively small (100-m-long) cave developed in Messinian gypsum in Emilia-Romagna (N. Italy). The surveys were carried out to compare the results obtained by both methods in mapping small-to medium-sized morphologies. These measurements allowed reconstructing the evolution stages of the paragenetic (anti-gravitative) morphologies (ceiling channels and pendants) that carved the roof of the cave, and their relationship with local geomorphology, infilling sediments, speleothems, and structural elements. Field measurements were integrated with morphometrical analyses of the digital models that then allowed a much greater number of observations to be made. The results are a clear example of how the combination of TLS and 3D-photogrammetric data can be used to study and measure mm-to dm-scale morphologies in geomorphological studies, including caves, helping to unravel the speleogenetic and, consequently, the hydrological evolution of these environments.

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... The cave surface can be modelled from the point cloud as a 3-D polygonal mesh or a 2.5-D raster surface, which was demonstrated in Gallay et al. (2016). Applications of TLS in non-glaciated caves are diverse, comprising the field of geomorphology (Cosso et al., 2014;Silvestre et al., 2014;Idrees and Pradhan, 2016;Fabbri et al., 2017;De Waele et al., 2018), studies on light conditions (Hoffmeister et al., 2014), archaeology (Gonzalez-Aguilera et al., 2009;Rüther et al., 2009;Lerma et al., 2010), and projects aiming to increase awareness and tourism (Buchroithner et al., 2011(Buchroithner et al., , 2012. However, the use of TLS in ice caves is possible but more challenging than in non-ice or exterior environments due to the slippery surface, harsh climate, and physical properties of ice, which absorbs a considerable portion of the shortwave infrared energy typically used by the laser scanner (Kamintzis et al., 2018). ...
... The ice accumulates in an open pit cave formed by the fall of the cave ceiling in lightcoloured Wetterstein limestone sediment between Anisian and Ladinian. The limestone bedding is inclined at 30 • with eastern orientation (Droppa, 1962). Silická l'adnica is classified as a static cave with congelation ice and firn (Luetscher and Jeannin, 2004). ...
... Roda et al. (1974) reported the ice area being from 710 to 970 m 2 and the ice volume being from 213 to 340 m 3 based on ice drilling and considering the precipitation and air temperature during the period before their measurement. Archaeological findings by Kunský, Roth, and Bohm, as reported by Droppa (1962) were used to estimate ice to be 2000 years old. ...
Article
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Ice caves can be considered an indicator of the long-term changes in the landscape. Ice volume is dynamic in the caves throughout the year, but the inter-seasonal comparison of ice dynamics might indicate change in the hydrological–climatic regime of the landscape. However, evaluating cave ice volume changes is a challenging task that requires continuous monitoring based on detailed mapping. Today, laser scanning technology is used for cryomorphology mapping to record the status of the ice with ultra-high resolution. Point clouds from individual scanning campaigns need to be localised in a unified coordinate system as a time series to evaluate the dynamics of cave ice. Here we present a selective cloud-to-cloud approach that addresses the issue of registration of single-scan missions into the unified coordinate system. We present the results of monitoring ice dynamics in the Silická ľadnica cave situated in Slovak Karst, which started in summer of 2016. The results show that the change of ice volume during the year is continuous and we can observe repeated processes of degradation and ice formation in the cave. The presented analysis of the inter-seasonal dynamics of the ice volume demonstrates that there has been a significant decrement of ice in the monitored period. However, further long-term observations are necessary to clarify the mechanisms behind this change.
... In addition, the user could move through complex cave passages with the MLS during the acquisition of the 3D point clouds without defining fixed stations, which provided quick and better results to cover the whole cave morphology. On the other hand, the TLS can provide more accuracy and precision due to the series of additional sensors such as an inclinometer, an electronic compass, and a dual-axis compensator (Jacquemyn et al., 2012;Fabbri et al., 2017;De Waele et al., 2018). At least 35 millions of points were acquired for each cave studied. ...
... We processed the point clouds with the open-source software Cloud Compare using the raw file from the LIDAR data. Cloud Compare offers several tools to improve the analysis of cave morphology and geometry (Fabbri et al., 2017;De Waele et al., 2018). MLS data were loaded to plot the intensity values of the scalar field using grayscale. ...
... Fabbri et al. (2017) used TLS to make detailed 3D models for morphometric measurements. De Waele et al. (2018) used TLS and 3D photogrammetry to identify different evolution stages of ceiling channels. Here, we applied both TLS and MLS to observe the karst geometry/shape (Figs. 3 and 7 e, 11 f); the MLS showed more accurate results due to the ability to move the instrument through both narrow and large cave passages without interrupting during acquisition. ...
Article
Caves developed in carbonate units have a significant role in fluid flow, but most of these subsurface voids are below seismic resolution. We concentrated our study on four caves to determine the roles of fractures and folds in the development of karst conduits that may form flow pathways in carbonate reservoirs. We performed structural field investigations, petrographic analyses, and geometric characterization using Light Detection and Ranging (LIDAR) for caves in Neoproterozoic carbonates of the Salitre Formation, central part of the São Francisco Craton, Brazil. We found that the conduit shape, usually with an ellipsoidal cross-section, reflects the tectonic features and textural variations. Carbonate layers containing pyrite and low detritic mineral contents are generally karstified and appear to act as favorable flow pathways. Our results indicate that the development of the karst system is related to fracture corridors formed along parallel and orthogonal sets of fold hinges, which provide preferential pathways for fluid flow and contribute to the development of super-K zones. This study provides insights into the prediction of subseismic-scale voids in carbonate reservoirs, with direct application for the hydrocarbon and hydrogeology flow and storage.
... Terrestrial laser scanning (TLS) can be considered as a technology suitable for noncontact measurement of spatial coordinates, 3D modeling, and visualization of complex underground structures (Cui et al., 2017;and others). During the last years, terrestrial laser scanning is widely used for the detailed survey of cave spaces and the study of cave morphology (Canevese et al., 2011;Jaillet et al., 2011;Cosso et al., 2014;Gallay et al., 2015Gallay et al., , 2016Silvestre et al., 2015;Oludare Idrees andPradhan, 2016, 2017;Fabbri et al., 2017;De Waele et al., 2018;and others). The high speed of scanning, accuracy, higher productivity versus common geodetic methods (such as selective measurement of individual points by total stations), significant shortening of fieldwork, and automatic data processing into digital models make this technology almost irreplaceable in rapid speleological mapping. ...
... Terrestrial laser scanning (TLS) can be considered as a technology suitable for non-contact measurement of spatial coordinates, 3D modeling, and visualization of complex underground structures (Cui et al., 2017;and others). During the last years, terrestrial laser scanning is widely used for the detailed survey of cave spaces and the study of cave morphology (Canevese et al., 2011;Jaillet et al., 2011;Cosso et al., 2014;Gallay et al., 2015Gallay et al., , 2016Silvestre et al., 2015;Oludare Idrees andPradhan, 2016, 2017;Fabbri et al., 2017;De Waele et al., 2018;and others). The high speed of scanning, accuracy, higher productivity versus common geodetic methods (such as selective measurement of individual points by total stations), significant shortening of fieldwork, and automatic data processing into digital models make this technology almost irreplaceable in rapid speleological mapping. ...
Book
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In the presented monograph, we documented the basic research of a geodetic survey of specific irregular surfaces. Based on the research on the behavior of different surfaces, various methods were proposed, and more complex methodological procedures to eliminate the influence of factors negatively affecting the application of non-contact surveying technologies were introduced. As part of the digital modeling of documented surfaces of objects, we tested their applicability, possibilities of various interpolation methods, and modeling techniques in the process of model creation. Technologies such as digital photogrammetry and laser canning bring new opportunities also in the documentation of the Earth’s surface. This combination of technologies allows us to use low-cost digital photogrammetry to document the Earth’s surface in relation to the documentation of geological phenomenon, mining activities, underground spaces, or special industrial applications. The book will also be a good source of information for students, scientists, but also professionals, in their studies, and scientific and professional works.
... For these reasons, TLS devices are often used in challenging environments like tunnels, galleries and hypogeal spaces. Due to their technical characteristics, they are useful to create highresolution 3D maps of underground areas such as natural caves, for geomorphological investigations, and to carry out measurements on hypogeal environments to document them as in (De Waele et al., 2018) and (Fabbri et al., 2017). As proposed in (Serna et al., 2015) the integration of 3D model from TLS and images makes possible the combining of geometric accuracy and texture quality allowing to reach a high level of photorealism. ...
Article
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Italian Cultural Heritage is rich in fascinating Underground Heritage (UH) to be protected and preserved because of its fragility and historical importance. An accurate and high-resolution 3D model is essential to reach an appropriate level of knowledge to safeguard caves but there are several obstacles to face. Underground data acquisition and following elaborations are problematic due to environmental conditions such as lack of homogeneous light sources, highly absorbing and unstable surfaces, narrow spaces and complex geometry. For these reasons, the integration of different techniques is mandatory to achieve a valid final product that could be an important basis for consolidation, preservation and valorization of the UH. In this paper, an integrated survey method is tested for a realistic digital reconstruction of hypogeal spaces. In addition to outputs for experts of conservation, the creation of multimedia products for a wider audience of non-professionals users is investigated as a way to preserve UH from decay. Thanks to VR, visitors virtually walk through the underground galleries observing and interacting, making accessible also fragile environments with forbidden access due to preservation policies.
... This makes measurement of slender, overhanging or highly complex objects difficult and likely to be under-estimated in terms of their rugosity, even if additional time is spent moulding the chain to complex/overhanging surfaces. The SfM technique shares this limitation of typically not being able to fully capture overhanging surfaces, however incorporating an increased number of oblique angle or upwards facing photos where possible (with appropriate lighting) will minimize this limitation and can allow vertical structures to fully overhanging cave systems to be imaged using SfM (Hernández et al., 2016;Robert et al., 2017;De Waele et al., 2018). ...
Article
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Reef structural complexity provides important refuge habitat for a range of marine organisms, and is a useful indicator of the health and resilience of reefs as a whole. Marine scientists have recently begun to use ‘Structure from Motion’ (SfM) photogrammetry in order to accurately and repeatably capture the 3D structure of physical objects underwater, including reefs. There has however been limited research on the comparability of this new method with existing analogue methods already used widely for measuring and monitoring 3D structure, such as ‘tape and chain rugosity index (RI)’ and graded visual assessments. Our findings show that analogue and SfM RI can be reliably converted over a standard 10-m reef section (SfM RI = 1.348 x chain RI—0.359, r2 = 0.82; and Chain RI = 0.606 x SfM RI + 0.465) for RI values up to 2.0; however, SfM RI values above this number become increasingly divergent from traditional tape and chain measurements. Additionally, we found SfM RI correlates well with visual assessment grades of coral reefs over a 10 x 10 m area (SfM RI = 0.1461 x visual grade + 1.117; r2 = 0.83). The SfM method is shown to be affordable and non-destructive whilst also allowing the data collected to be archival, less biased by the observer, and broader in its scope of applications than standard methods. This work allows researchers to easily transition from analogue to digital structural assessment techniques, facilitating continued long-term monitoring, whilst also improving the quality and additional research value of the data collected.
... All of the caves show the typical configuration of epigenic gypsum caves, appearing as simple horizontal tunnels connected to lower or upper levels (if present) by vertical shafts (Klimchouk et al., 1996). The planimetry of the caves follows the WNW-ESE Apennine-like and the NE-SW anti-Apennine like directions (Ghiselli et al., 2011), a common feature in the Romagna sector (De Waele et al., 2018a). ...
Article
High-resolution U-Th and 14C dating of two calcite flowstones (RTf: Last Interglacial; RTy: Late Holocene) from the Re Tiberio – Monte Tondo karst system (North Italy) is presented to investigate the palaeoclimate potential of speleothems from gypsum caves. To date, there is a lack of information regarding the dating potential of calcite speleothems that have grown in such gypsum karst environment (e.g. no pseudokarst). High-resolution U-Th dating, aimed at establishing if these speleothems can provide robust radiometric age sequences, is first presented. Although both samples show promise for reliable radiometric dating, about 20% of the ages in the RTf dataset were excluded from the age-model as outliers. These outliers are best explained by post-depositional diagenetic processes affecting the U-Th system rather than anything specific to gypsum karst environment conditions. In contrast, outliers were not detected in the RTy sample, but U-Th analysis was not able to constrain its relatively young age (∼600 years before present, B.P.). Consequently, radiocarbon measurements were undertaken, and combined with the U-Th ages to build an age-model. The latter allowed the estimation of “dead carbon fraction” (DCF), which yields a constant value through time, and a magnitude comparable to other sites where climate is similar to Monte Tondo. Soils were considered the main source of carbon, because bedrock dissolution acted predominantly under open-system conditions, and soil organic matter (SOM) turnover rate appears above average compared to sites studied elsewhere.
... Terrestrial laser scanners (TLSs) have been extensively used in underground environments for a wide spectrum of applications, ranging from archaeology to geomorphology, from palaeontology/paleoclimatology to ecology/biology and visualization and education (Fabbri et al., 2017;Mohammed Oludare & Pradhan, 2016). Examples of photogrammetric surveying have also been reported in the literature, in comparison (Pukanská et al., 2017) or combination with TLS (De Waele et al., 2018;Rodríguez-Gonzálvez et al., 2015). Recently, fisheye lenses have been successfully employed in natural (Alessandri et al., 2019) and man-made narrow spaces (Perfetti et al., 2017). ...
Article
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Underwater caves represent the most challenging scenario for exploration, mapping and 3D modelling. In such complex environment, unsuitable to humans, highly specialized skills and expensive equipment are normally required. Technological progress and scientific innovation attempt, nowadays, to develop safer and more automatic approaches for the virtualization of these complex and not easily accessible environments, which constitute a unique natural, biological and cultural heritage. This paper presents a pilot study realised for the virtualization of 'Grotta Giusti' (Fig. 1), an underground semi-submerged cave system in central Italy. After an introduction on the virtualization process in the cultural heritage domain and a review of techniques and experiences for the virtualization of underground and submerged environments, the paper will focus on the employed virtualization techniques. In particular, the developed approach to simultaneously survey the semi-submersed areas of the cave relying on a stereo camera system and the virtualization of the virtual cave will be discussed.
... The advantage of using passive sensors is that they do not require elaborate data acquisition planning, and data processing is also very easy for non-expert operators. Some recent studies described the application of 3D photogrammetric techniques on small areas of dark caves [6,21,22] or as an integration into the terrestrial laser scanning (TLS) approach [23]. ...
Article
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The geomatic survey in the speleological field is one of the main activities that allows for the adding of both a scientific and popular value to cave exploration, and it is of fundamental importance for a detailed knowledge of the hypogean cavity. Today, the available instruments, such as laser scanners and metric cameras, allow us to quickly acquire data and obtain accurate three-dimensional models, but they are still expensive, require a careful planning phase of the survey, as well as some operator experience for their management. This work analyzes the performance of a smartphone device for a close-range photogrammetry approach for the extraction of accurate three-dimensional information of an underground cave. The image datasets that were acquired with a high-end smartphone were processed using the Structure from Motion (SfM)-based approach for dense point cloud generation: different image-matching algorithms implemented in a commercial and an open source software and in a smartphone application were tested. In order to assess the reachable accuracy of the proposed procedure, the achieved results were compared with a reference dense point cloud obtained with a professional camera or a terrestrial laser scanner. The approach has shown a good performance in terms of geometrical accuracies, computational time and applicability.
... Since the image processing is almost automatic (James and Robson, 2012), little expertise needs to use 3D-PR techniques. Furthermore, recent applications in soil erosion (Castillo et al., 2012;Gómez-Gutiérrez et al., 2014;Kaiser et al., 2014;Di Stefano and Ferro, 2016) or in cave morphologies (De Waele et al., 2018) demonstrated that high accurated DTMs can be obtained. The use of Structure from Motion (SfM) technique is integrated with MultiView-Stereo (MVS) workflows (Seiz et al., 2006;Westoby et al., 2012;Javernick et al., 2014) in software packages such as Photoscan (Agisoft) (Frankl et al., 2015). ...
Article
Rillenkarren are small scale, straight, narrow solution channels that head at the crest of a bare rock slope and are extinguished downslope. In this paper the applicability of 3D-photo reconstruction technique of the rock surface is proposed for capturing the rillenkarren morphometry on gypsum. At first, the measurements are used to assess a relationship between the width/depth ratio and the depth of the rillenkarren. The exponent of this power relationship resulted different from the theoretical value - 0.5, confirming that the cross-section profiles of a rillenkarren can have a shape different from parabolic. The analysis developed for the cross-section area, the perimeter and the hydraulic radius established that the formation process is able to deep and enlarge the channel. The proposed model of the measured longitudinal profiles confirmed that the profile shape can be characterized by a flex point which divide the upstream concave part from the downstream convex one. According to previous studies on soil erosion features (rills, ephemeral gullies and gullies) the relationship between the rillenkarren length and its volume was expressed by a power equation. The comparison between rillenkarren and soil erosion features allowed to conclude that a single exponent (equal to 1.1) can be applied while the coefficient is characteristic of the feature and represents the influence of channel depth and width. Finally a model of rillenkarren morphometry, deduced applying the dimensional analysis and self-similarity, was applied to the measurements. This analysis demonstrated that a single dimensionless relationship is applicable to rillenkarren and rills, ephemeral gullies and gullies, assessing that a morphometric similarity exists between these different erosion features.
... Typically conducted using only consumergrade cameras, DEM built from SfM-MVS photogrammetry employs highly portable sensors, which is a key consideration for many applications, such as extraterrestrial field surveys (Caravaca et al., 2019), mapping of caves and mines (e.g. De Waele et al., 2018;Triantafyllou et al., 2019), or in challenging/poorly accessible exposures (Bistacchi et al., 2015;Giuffrida et al., 2020). The low cost of consumer-grade cameras has had a transformative impact upon the uptake of close-range remote sensing within the geosciences, providing an egalitarian approach to DEM generation, which is practically available to all. ...
Article
Smartphones can be regarded as cameras, natively equipped with geolocation and orientation sensors, making them powerful, portable, user-friendly and inexpensive tools for terrestrial structure from motion/multiview stereo photogrammetry (SfM-MVS) surveys. Camera extrinsic parameters (i.e. camera position and orientation), required to produce fully georeferenced SfM-MVS 3D models are available for the majority of smartphone images via inbuilt magnetometer, accelerometer/gyroscope, and global navigation satellite system (GNSS) sensors. The precision of these internal sensors is not yet sufficient to directly use them as input to SfM-MVS photogrammetric reconstructions. However, when the reconstructed scene is significantly greater than the positional error, camera extrinsic parameters can be successfully used to register 3D models during post-processing. We present a survey of a 400 m wide vertical cliff to illustrate a workflow that enables the use of smartphone cameras to generate and fully georeference photogrammetric models without employing ground control points. Survey images were acquired at a distance of ~350 m to the mapped scene using a consumergrade smartphone. This survey image dataset was subsequently used to build an unreferenced 3D model, which was registered during postprocessing using orientation and position metadata tagged to each photograph. This ms has been accepted for publication in the journal Geomorphology
... Terrestrial Laser Scanning (TLS) can be considered as a technology suitable for non-contact measurement of spatial coordinates, 3D modeling, and visualization of complex underground structures ( [18] and others). During the last years, terrestrial laser scanning has been widely used for the detailed survey of cave spaces and the study of cave morphology ( [19][20][21][22][23][24][25][26][27][28] and others). The high speed of scanning, accuracy, higher productivity versus common geodetic methods (such as selective measurement of individual points by total stations), significant shortening of fieldwork, and automatic data processing into digital models make this technology almost irreplaceable in rapid speleological mapping. ...
Article
Full-text available
The Ochtiná Aragonite Cave (Slovakia, Central Europe) is a world-famous karst phenomenon of significant geological, geomorphological, and mineralogical values. Its specific origin is determined by particular lithological and hydrogeological conditions of the Ochtiná karst formed in lenses of Paleozoic crystalline limestones, partly metasomatically altered to ankerite and siderite. Although the cave is only 300 m long, it represents a combined labyrinth consisting in parallel tectonically controlled halls and passages, that are largely interconnected through transverse conduits of phreatic and epiphreatic morphology with many medium-and small-scale forms originated in slowly moving or standing water (flat solution ceilings, wall inward-inclined facets, water table notches, convectional cupolas, and spongework-like hollows). The highly dissected and irregular morphologies of the cave were surveyed with terrestrial laser scanning and digital photogrammetry. Both used surveying technologies proved to be suitable for quick and accurate mapping of the complicated cave pattern. While terrestrial laser scanning can provide a rapid survey of larger and more complex areas with results delivered directly in the field, digital photogrammetry is able to generate very high-resolution models with quality photo-texture for mapping of small-scale morphologies. Several data on cave morphometry were generated from terrestrial laser scanning (e.g., the area of cave ground plan, the peripheral surface of underground spaces, and their volume). The new detailed map, sections, and 3D model create an innovation platform for a more detailed study on the morphology and genesis of this unusual cave also for its environmental protection and use in tourism.
... For the purposes of this study, GeoSLAM is superior to conventional terrestrial laser scanning because it does not require the bulky equipment and cumbersome setups that are ill suited for cave environments, where narrow and tortuous passages make stop-and-scan strategies difficult. Such systems are, however, possibly adapted for smaller caves or specific parts of larger caves (De Waele et al., 2018). ...
Article
The Morro Vermelho Cave (MVC) (Brazil) developed within the Morro Vermelho karst system, which affected Neoproterozoic limestones (Salitre Formation). The MVC experienced little interactions with meteoric processes and is an example of a hypogenic cave formed during strike-slip deformation. The Salitre carbonates in the MVC experienced distributed deformation along an elongated domain overlying a buried strike-slip fault. Gently dipping, semiductile shear zones formed with decimeterscale (3.9 in.) dolomitic veins. In our model, Mg-rich fluids flowing along the Salitre aquifer caused at the same time extensive dolomitization of the body of rock (100-m [328-ft] scale) experiencing distributed deformation. With progressive displacement, the deep strike-slip fault propagated upward causing the development of an anticline pop-up, steepening sedimentary layers, and steep 1–10-m-long (3.3–33.8-ft) fractures, which served as pathways for upward fluid flow. These steep extensional fractures made it possible for fluids flowing in lower, quartzitic aquifers to enter the carbonate aquifer causing silica deposition in rock cavities and in fractures and fault planes. Following the main stage of speleogenesis, silica deposition took over again depositing on the cave walls a continuous silica crust, rarely observed in other settings worldwide. The interplay between regional beddingparallel flow and focused circulation of fluids along steep faults and dipping layers, and the associated rock–fluid interactions are not unique to the contractional settings presented but can also occur in association with similar faults in rifted continental margins.
... The point clouds come from 24 stations, spaced 10 to 20 m apart, and distributed over the entire site with 6 min per station for black and white scanning for 21 stations and 15 min for color scanning for 3 stations. (González Aguilera et al., 2009;Sadier, 2013;Grussenmeyer et al., 2015;Pamart et al., 2019;Melnikova et al., 2015;Leonov et al., 2014;De Waele et al., 2018;Jaillet, 2014;Robert et al., 2014;Maumont, 2010). The range of the used scanner could be up to 70 m, with a vertical rotation of 300 degrees and horizontal of 360 degrees, and approximately 1,000,000 dots/second. ...
Article
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From the middle of the 19th century, speleological topography became a discipline, if not an art, which supported the work of both explorers and scientists. Underground explorations in Morocco remain an area to be discovered and developed. The Moroccan 99,890 km² limestone surface, represents 14% of the total surface which potentially contains a large number of caves, only 3 of them are developed. This under-exploitation is explained by the lack of evaluation of the richness of Morocco’s karst and cave heritage, the topographic maps of Moroccan Caves are poorly carried out or absent, the last inventory of Moroccan Caves dates from 1981.The objective of this study is to represent the AZIZA Cave virtually, appreciate its volume, and optimize the topography of the latter based on 3D technologies. Two methods were used, the topography of the cave by a DISTO-X, and the results of the 3D projection of the cave were carried out on the software VISUAL TOPO. Secondly, we carried out 3D modeling by lasergrammetry using a TLS FARO FOCUS 70, to scan the main entrance, the main axes, and the large rooms of the AZIZA Cave, the final rendering was provided by the scene software. Laser grammetry gave us the possibility of having a virtual representation of the cave and also of important details that conventional methods cannot give because of this heritage dimension, conservation conditions are essential, also given the potential to be appreciated that the cave and its environment offer, which can constitute a typical example of the exploitation of karst heritage and its environment.
... This area is well known for its natural and scientific interest (see Fig. 1). The Ca' Castellina gypsum cave is located at the bottom of the nearby doline immediately West of the quarry, and is an important palaeoclimatic and palaeoenvironmental site witnessing the hydrology and sedimentation occurred previous to the Last Glacial Maximum (De Waele et al., 2018). Another important archaeological cave, the Grotta dei Banditi, opens on the southern slopes of Mt. ...
Article
Roman-period extractive sites in gypsum outcrops are very rare, and most have become very degraded by later weathering or quarrying activities. This paper describes, using laser scanning, photogrammetry and survey using a UAV-based survey, the uniquely well-preserved Roman-period gypsum quarry of Ca’ Castellina (Northern Apennines, Italy). This site was excavated only in the last few years and the excavations have brought to light some gypsum blocks and the ancient quarry benches showing excavation marks, the remains of a rectangular building and a great number of artefacts that range between the Protohistoric Period and the modern times. The size of the extracted blocks, the extraction methodologies and the age of a charcoal fragment (361 – 178B CE) found immediately at the contact between the gypsum quarry floor and the infilling sediments date the quarry back to the Roman age. Archaeological evidences demonstrate the building to have been used for a short period of time during the XVI-XVII century. Immediately after its abandonment most of the quarry floor has been covered with a thick detrital layer, protecting it from dissolution (fossilizing this floor and leaving it as if it was abandoned very recently), whereas the naked or poorly covered floor of this quarry has been subjected to dissolution phenomena of the exposed gypsum rocks, with a lowering of the surface, the smoothening of the corners and the formation of a set of deeply carved karren features. A 3D survey using both a laser scanning instrument and a drone-mounted photo camera have allowed to get precise measures on the size of the blocks that were extracted in this quarry, the traces of pick axe marks, and on the dissolution morphologies that have developed on the bare gypsum rock. These typical gypsum landforms show how fast these solution forms can develop where concentrated runoff flows on bare gypsum. To prevent this exceptional archaeological extractive site of being further dissolved, it will be important to plan some measures to be put in place in order to protect this delicate historical landmark.
... In particular, 3D digital models of caves are suitable tools for both scientific purposes. They can be used for geological or geomorphological observations [2], for the integration of 3D underground caves cadastral databases [3], and visualization and navigation, especially related to complex access caves, through virtual and augmented reality techniques [4]. In geomatics, several well-established methods are available for the three-dimensional survey of environments. ...
Article
Full-text available
A three-dimensional survey of natural caves is often a difficult task due to the roughness of the investigated area and the problems of accessibility. Traditional adopted techniques allow a simplified acquisition of the topography of caves characterized by an oversimplification of the geometry. Nowadays, the advent of LiDAR and Structure from Motion applications eased three-dimensional surveys in different environments. In this paper, we present a comparison between other three-dimensional survey systems, namely a Terrestrial Laser Scanner, a SLAM-based portable instrument, and a commercial photo camera, to test their possible deployment in natural caves survey. We presented a comparative test carried out in a tunnel stretch to calibrate the instrumentation on a benchmark site. The choice of the site is motivated by its regular geometry and easy accessibility. According to the result obtained in the calibration site, we presented a methodology, based on the Structure from Motion approach that resulted in the best compromise among accuracy, feasibility, and cost-effectiveness, that could be adopted for the three-dimensional survey of complex natural caves using a sequence of images and the structure from motion algorithm. The methods consider two different approaches to obtain a low resolution complete three-dimensional model of the cave and ultra-detailed models of most peculiar cave morphological elements. The proposed system was tested in the Gazzano Cave (Piemonte region, Northwestern Italy). The obtained result is a three-dimensional model of the cave at low resolution due to the site’s extension and the remarkable amount of data. Additionally, a peculiar speleothem, i.e., a stalagmite, in the cave was surveyed at high resolution to test the proposed high-resolution approach on a single object. The benchmark and the cave trials allowed a better definition of the instrumentation choice for underground surveys regarding accuracy and feasibility.
... LiDAR technology has also proven to be a valuable tool in geological mapping studies (Buckley et al., 2008;Drews et al., 2018), elaboration of digital elevation models (DEMs) (Slob et al., 2002), and virtual outcrop models of hydrocarbon reservoir analogs (Bellian et al., 2005;Enge et al., 2007;Fabuel-Perez et al., 2010;Marques et al., 2020). In 3D cave mappings, ground-based LiDAR data promote a change of perspective in geomorphological studies by allowing the analysis of the morphology and volume of the voids and conduits (Silvestre et al., 2015;Gallay et al., 2016;De Waele et al., 2018) and the analysis of structural and hydrogeological characteristics of the cave bedrock (Buchroithner and Gaisecker, 2009). ...
Article
The present study used a multitool approach to characterize fractures of several orders of magnitude in large fracture corridors, caves, and canyons to investigate their impact on fluid flow in carbonate units. The study area is the Brejões carbonate karst system that is located in the Neoproterozoic Salitre Formation in the Irecê Basin, São Francisco Craton, Brazil. The approach included satellite images, used for interpreting the regional structural context, Unmanned Aerial Vehicle (UAV) and ground-based Light Detection And Ranging (LiDAR) imagery, used for detailed structural interpretation. Regional interpretation revealed that fracture corridors, caves and canyons occur along a hinge of a N–S-oriented anticline. An advanced stage of karstification caused fracture enlargement and intrabed dissolution, and the formation of caves and canyons. A river captured by the highly fractured zone along the anticline hinge played an important role as an erosive agent. Detailed characterization of fracture corridors comprised classic structural analysis, topological studies, persistence estimations, power-law fitting of fracture trace length distributions, and identification of network backbones. Our results indicate that fracture corridors comprise four subvertical fracture sets: N–S and E-W and a conjugate pair, NNE-SSW and NW-SE. Fractures observed in the caves show the same dominant directions. Fracture directions are consistent with a common origin associated with the anticline folding. Fracture traces range from 1.0 m to 300 m, comprising both subseismic (<50 m) and seismic scale fractures (>50 m). Networks have dominance of node terminations Y and X (notably Y), CB values higher than 1.8, high P20 and P21 persistence values, and highly interconnected backbones. Fracture network connectivity is associated with power-law exponents greater than 2.5 for the fracture trace distributions, indicating large influence of subseismic-scale fractures on fluid flow. As the final result of folding and karstification, large volumes of secondary macroporosity were created, particularly in the zone of maximum fracture intensity around the hinge zone of the anticline. This scenario can be used to understand better oil reservoirs formed in similar structural controls in near-surface conditions.
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The Natzweiler-Struthof camp is the only concentration camp in France, in Alsace. In 1941, when the construction of this camp began, the Nazi regime had already set up several concentration camps in annexed territory. The purpose of this camp was mainly to intern the resistance considered dangerous for the regime. From a chronological point of view, the camp integrated in May 1941 its first prisoners. They were condemned to carry out inhumane work until the evacuation of the camp on September 2, 1944. The Natzweiler-Struthof camp was associated with a granite quarry where we can still find concrete foundations of old buildings as well as three galleries excavated with explosives. The digitization work aims to archive, analyze and understand the organization and operation to result in a 3D reconstruction of the site. In 2018, the Struthof site began a major restoration project. For the first time in this camp, an archaeological diagnosis was then made with the aim of understanding the still existing facilities and assuming the presence of other elements now destroyed. To deepen the knowledge on this camp, the Regional Administration of Cultural Affairs authorized in 2020 to carry out prospecting accompanied by a study of the built-up in an area still empty of research: the quarry. Currently, this part of the camp shows the remains of three buildings and three galleries. To know more about these elements and indirectly about the life of the camp and its prisoners, this study shows the approach adopted to prepare the 3D modeling of buildings and galleries.
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Topography is the most important component of the geographical shell, one of the main elements of geosystems, and the framework of a landscape. geomorphometry is a science, the subject of which is modeling and analyzing the topography and the relationships between topography and other components of geosystems. Currently, the apparatus of geomorphometry is widely used to solve various multi-scale problems of the Earth sciences. As part of the RFBR competition “Expansion”, we present an analytical review of the development of theory, methods, and applications of geomorphometry for the period of 2016–2021. For the analysis, we used a sample of 485 of the strongest and most original papers published in international journals belonging to the JCR Web of Science Core Collection quartile I and II (Q1–Q2), as well as monographs from leading international publishers. We analyze factors caused a progress in geomorphometry in recent years. These include widespread use of unmanned aerial survey and digital photogrammetry, development of tools and methods for survey of submarine topography, emergence of new publicly available digital elevation models (DEMs), development of new methods of DEM preprocessing for their filtering and noise suppression, development of methods of two-dimensional and three-dimensional visualization of DEMs, introduction of machine learning techniques, etc. We consider some aspects of the geomorphometric theory developed in 2016–2021. We discuss new computational methods for calculating morphometric models from DEM, as well as the problems facing the developers and users of such methods. We consider application of geomorphometry for solving multiscale problems of geomorphology, hydrology, soil science, geology, glaciology, speleology, plant science and forestry, zoogeography, oceanology, planetology, landslide studies, remote sensing, urban studies, and archaeology.
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Abandoned mine lands are a common element of the contemporary landscape. In administrative practice, they are rated low, yet they are of interest to informal users and scientific and cultural communities. The aim of the research was to identify the possibilities of using qualitative research methods, applied in architecture, to create friendly, urban spaces with a universal character in the areas of abandoned quarries. The study was conducted in the Sadowa Góra quarry area in southern Poland, using Post Occupancy Evaluation (POE) method. The results of the conducted analysis confirm the effectiveness of the POE method in restoring abandoned mine lands to economically usable state by surveying users' opinions on accessibility, functionality, and visual quality. The applied methodology was used as an effective support for the transformation process of post‐mining areas and as a tool to optimize the costs of their reclamation and maintenance. This article is protected by copyright. All rights reserved.
Chapter
This chapter deals with the morphology of the subterranean world accessible to human beings: caves. It also focuses on the gross morphology of dissolution caves, which are the great majority of the caves on Earth. Many geomorphology textbooks adopt a process‐landform‐based approach to describe the different types of geomorphic features, grouping them according to the most common zonal or azonal geomorphic system in which they develop. Caves can form by a variety of processes, which can be categorized into the following groups: dissolution, weathering and erosion, mechanical movement and accumulation, deposition, melting, and solidification. The roofs, walls, and floors of cave passages can be sculpted by medium‐ to small‐scale morphological features formed by solution and mechanical erosion, collectively designated as speleogens. These morphologies carved in the rock can provide valuable information on the processes that were active in the cave passages, especially in the latest (more recent) stages of their development.
Technical Report
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Eye-Dome Lighting (EDL) is a non-photorealistic, image-based shading technique designed to improve depth perception in scientific visualization images. It relies on efficient post-processing passes implemented on the GPU with GLSL shaders in order to achieve interactive rendering. Solely projected depth information is required to compute the shading function, which is then applied to the colored scene image. EDL can, therefore, be applied to any kind of data regardless of their geometrical features (isosurfaces, streamlines, point sprites, etc.), except to those requiring transparency-based rendering.
Conference Paper
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Terrestrial LIDAR (T-Lidar, or 3-D) scanning gives outstanding detail in cave surveying, generating extremely large datasets of dense point clouds, resulting in very detailed and precise 3D models of the scanned caves. These models are commonly used to determine the volume of chambers. Intuition tells us that the denser the point cloud, the better it will fit the real dimensions of the cave. Here we prove that this is not the case. We show that with a low number of measured points it is possible to calculate volumes which will match the true volumes of a cavity with high precision. Scanning at extremely coarse resolution with angles as high as 4.3° (approximately 1/400 of full resolution) gives a good estimate of volume, although detail is not rendered. The linear relationship between the distance of the scanner and the scanned resolution of the cave wall indicates that < 1 cm-scale detail can be rendered by scanning at ¼ resolution up to ~20 m distance. For the same detail, at distances between ~20 and ~70 m, scanning at higher resolution will be required. It is not possible, even with full resolution, to get centimetre-scale detail at distances greater than ~70 m. Therefore, it is apparent that scanning caves at only ¼ resolution is generally quite sufficient to represent the real volume of the cave and most of the detail.
Conference Paper
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As part of activities of the " Inside the Glaciers " project, managed by an Italian team of speleologists and geologists with the purpose of studying several ice-caves in Europe and South America, a research campaign was recently carried out in Mount Etna (Sicily, Italy). This volcano is the highest active in Europe and hosts more than 200 caves including Grotta del Gelo (Ice Cave) which is located on the Northern flank of Mount Etna at an altitude of about 2040 m a.s.l. This cave was formed during the Etna's long and most destructive eruption dated from 1614 to 1624 and is one of the most famous because it hosts a small glacier, maybe the southernmost of the Northern hemisphere. Aim of this project was to realize a detailed survey of Grotta del Gelo using a Leica HDS 7000 terrestrial laser scanner in order to acquire precise data measurements of the ice deposits. This survey was the first step of a monitoring project that will be developed in the next years in collaboration with the Etna Regional Park, the Sicilian Regional Speleological Federation and the Centro Speleologico Etneo of Catania which by many years are involved in the topographic monitoring of this particular cave. The proposed article introduces the methods used for this first laser scanning survey campaign of Grotta del Gelo and the results obtained.
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Although outcropping rarely in Italy, evaporite (gypsum and anhydrite) karst has been described in detail since the early 20 th century. Gypsum caves are now known from almost all Italian regions, but are mainly localised along the northern border of the Apennine chain (Emilia Romagna and Marche), Calabria, and Sicily, where the major outcrops occur. Recently, important caves have also been discovered in the underground gypsum mines in Piedmont. During the late 80s and 90s several multidisciplinary studies were carried out in many gypsum areas, resulting in a comprehensive overview, promoting further research in these special karst regions. More recent and detailed studies focused on the gypsum areas of Emilia-Romagna and Sicily. Sinkholes related to Permian-Triassic gypsum have been studied in Friuli Venezia Giulia. This article reviews the state of the art regarding different aspects of evaporite karst in Italy focusing on the main new results.
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has traditionally been undertaken by tacheometric surveying methods. These methods are excellent for capturing the general shape of a cave system but they are not suitable for high-speed, high-resolution mapping of complex surfaces found in this environment. Terrestrial laser scanning (TLS) technologies can acquire millions of points represented by 3-D coordinates, at very high spatial densities on complex multifaceted surfaces within minutes. In the last few years, advances in measurement speed, reduction in size / cost and increased portability of this technology has revolutionised the collection of 3-D data. This paper discusses the methodological framework and the advantages / disadvantages of adopting terrestrial laser scanning to rapidly map a complex cave system on the example of the Domica Cave in Slovakia. This cave originated in the largest karst region in the West Carpathians. The collected data set or ‘point cloud’ contains over 11.9 billion of measured points, captured in 5 days from 327 individual scanning positions. The dataset represents almost 1,600 m of the cave passages. Semi-automatic registration of these scans was carried out using reference spheres placed in each scene and this method archived an overall registration error of 2.24 mm (RMSE). Transformation of the final registered point cloud from its local coordinate system to the national cartographic system was achieved with total accuracy of 21 mm (RMSE). This very detailed data set was used to create a 3-D cave surface model needed for volumetric analyses. In the future, it will be used for spatial analyses or simulating the interaction of surface and subsurface processes contributing to the development of the cave system on the basis of a 3-D GIS platform.
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Gypsum beds host the majority of the caves in the north-eastern flank of the Apennines, in the Emilia Romagna region (Italy). More than six hundred of these caves have been surveyed, including the longest known epigenic gypsum cave systems in the world (Spipola-Acquafredda, ~11 km). Although this area has been intensively studied from a geological point of view, the age of the caves has never been investigated in detail. The rapid dissolution of gypsum and uplift history of the area have led to the long-held view that speleogenesis commenced only during the last 130,000 years. Epigenic caves only form when the surface drainage system efficiently conveys water into the underground. In the study area, this was achieved after the dismantling of most of the impervious sediments covering the gypsum and the development of protovalleys and sinkholes. The time necessary for these processes can by constrained by understanding when caves were first formed. The minimum age of karst voids can be indirectly estimated by dating of the infilling sediments. U-Th dating of carbonate speleothems growing in gypsum caves has been applied to 20 samples from 14 different caves from the Spipola-Acquafredda, Monte Tondo-Re Tiberio, Stella-Rio Basino, Monte Mauro, and Castelnuovo systems. The results show that: i) caves were forming since at least ~600 kyrs ago; ii) the peak of speleogenesis was reached during relatively cold climate stages, when rivers formed terraces at the surface and aggradation caused paragenesis in the stable cave levels; iii) ~200,000 years were necessary for dismantling of most of the sediments covering the karstifiable gypsum and the development of a surface mature drainage network. Besides providing a significant contribution to the understanding of evaporite karst evolution in the Apennines, this study refines our knowledge on the timescale of geomorphological processes in a region affected by rapid uplifting.
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The change of hydrological conditions during the evolution of caves in carbonate rocks often results in a complex subterranean geomorphology, which comprises specific landforms such as ceiling channels, anastomosing half tubes, or speleothems organized vertically in different levels. Studying such complex environments traditionally requires tedious mapping; however, this is being replaced with terrestrial laser scanning technology. Laser scanning overcomes the problem of reaching high ceilings, providing new options to map underground landscapes with unprecedented level of detail and accuracy. The acquired point cloud can be handled conveniently with dedicated software, but applying traditional geomorphometry to analyse the cave surface is limited. This is because geomorphometry has been focused on parameterization and analysis of surficial terrain. The theoretical and methodological concept has been based on two-dimensional (2-D) scalar fields, which are sufficient for most cases of the surficial terrain. The terrain surface is modelled with a bivariate function of altitude (elevation) and represented by a raster digital elevation model. However, the cave is a 3-D entity; therefore, a different approach is required for geomorphometric analysis. In this paper, we demonstrate the benefits of high-resolution cave mapping and 3-D modelling to better understand the palaeohydrography of the Domica cave in Slovakia. This methodological approach adopted traditional geomorphometric methods in a unique manner and also new methods used in 3-D computer graphics, which can be applied to study other 3-D geomorphological forms.
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During the last decade, the need to survey and model caves or caverns in their correct three-dimensional geometry has increased due to two major competing motivations. One is the emergence of medium and long range terrestrial laser scanning (TLS) technology that can collect high point density with unprecedented accuracy and speed, and two, the expanding sphere of multidisciplinary research in understanding the origin and development of cave, called speleogenesis. Accurate surveying of caves has always been fundamental to understanding their origin and processes that lead to their current state and as well provide tools and information to predict future. Several laser scanning surveys have been carried out in many sophisticated cave sites around the world over the last decade for diverse applications; however, no comprehensive assessment of this development has been published to date. This paper reviews the state-of-the-art three-dimensional (3D) scanning in caves during the last decade. It examines a bibliography of almost fifty high quality works published in various international journals related to mapping caves in their true 3D geometry with focus on sensor design, methodology and data processing, and application development. The study shows that a universal standard method for 3D scanning has been established. The method provides flexible procedures that make it adaptable to suit different geometric conditions in caves. Significant progress has also been recorded in terms of physical design and technical capabilities. Over time, TLS devices have seen a reduction in size, and become more compact and lighter, with almost full panoramic coverage. Again, the speed, resolution, and measurement accuracy of scanners have improved tremendously, providing a wealth of information for the expanding sphere of emerging applications. Comparatively, point cloud processing packages are not left out of the development. They are more efficient in terms of handling large data volume and reduced processing time with advanced and more powerful functionalities to visualize and generate different products.
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The morphological knowledge of the territory, both in its surface and subterranean aspects, is the main premise to all decision-making procedures as well as all planning and management activities. Knowledge takes shape into reliable precise and complete thematic cartography and databases, which are necessary for anybody dealing with underground contexts: speleologists, scientists, public administrations, managing authorities etc. Surveys in caves are normally carried out with traditional techniques and instruments, which are essential for a first representation but not enough for a pragmatic effective topographic approach. Laser scanning technique can be an alternative to the traditional systems. Laser scanning quickly acquires the shape of cavities as "point clouds" (x, y, z coordinates and colour values) and produces a high precision database of the surveyed object. Laser scanning technology is therefore a feasible way to document caves in a precise exhaustive way, limiting risks relating to lack and/or inadequacy of data. The present paper explains the laser scanning survey carried out in San Giovanni mine near Iglesias (Sardinia, Italy), particularly in Santa Barbara and Santa Barbara 2 caves, the data post-processing and three-dimensional modelling of "point clouds" (operations performed with a dedicated software), and the use of the obtained digital model. Moreover, the paper describes the advantages of laser scanning for the hypogean survey in comparison to traditional methods and the future potentialities of a broad application of laser scanning instruments in caves.
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At the turn of the 20th century, the practical examination of caves went through a radical change. Governmental organizations and private clubs were founded in an attempt to establish speleology as an independent academic subject. In contrast to earlier cave visitors, travelers began entering underground areas and attributing the names of “explorers” or “researchers” to themselves. Fieldwork—especially cave surveying and cartography—became common practice in speleology and such work provided important clues on speleogenesis, which was a controversial issue in the first half of the 20th century. Due to the fact that speleologists began separating themselves from ordinary cave visitors and tourists, tools and instruments for cave exploration and mapping, such as carbide lamps, ropes, compasses, clinometers, and drawing boards, became the emblems of speleology. Through historical discourse analysis, this paper examines whether this change in the status and practice of underground fieldwork had an effect on the self-perception of speleology and led to new forms of social cooperation and control between speleologists. Further questions address the manner in which the usage of new surveying instruments and the relevance of cave mapping modified the scientific research parameters and the cultural perceptions of the subterranean world. As a contribution to speleo-history, this approach opens a new perspective on the social and cultural dimensions of speleological fieldwork as well as the historical, scientific, and political dynamics in which they were involved. Sources for this research comprised historical scientific papers on cave mapping, textbooks, and archive materials from the Austrian National Library, the Natural History Museum in Vienna, and the Austrian Speleological Association.
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Gaius Plinius Secundus, better known as Pliny the Elder, Roman naturalist and philosopher who lived between AD 23-79, described a particular and transparent stone known as Lapis Specularis, widely used in Roman times for the production of door and window panels. This particular stone similar to glass was quarried in many areas of the Roman Empire in Spain, Italy, Greece and North Africa from cavities or natural gorges, trying to follow the fractures in which this rock was formed. The stone is gypsum in its secondary macrocrystalline form that may be easily split to form thin transparent sheets. The first exploitation site for Lapis Specularis discovered in Italy is located in a cave called " Grotta della Lucerna ". This name derives from the discovery of some Roman lamps used by miners to lighten the cave during the mining operations. This paper describes the detailed laser scanner survey that we performed in this important archeological site.
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A third phase of investigation of the Peak Cavern Vestibule, using cutting-edge LIDAR total station equipment, obtained a 16.8 million co-ordinate data point cloud, which was re-sampled into a digitally-rendered, 3-D triangular surface model. Visualisation software allows dynamic viewing of the data model from any angle or orientation, with editing software allowing picking, interpretation and horizon generation of geological features of interest. Model analyses of surface 'en-echelon' joints reveal an anticlinal fold hinge mid-way through the Vestibule. Bedding planes were found to be sub-horizontal but parallel to the Vestibule main body axis.
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High resolution terrestrial laser scanning (TLS) within the Simud Hitam Cave, Gomantong, has proven successful at discriminating the nests of black-nest swiftlets from roosting bats in high, inaccessible locations. TLS data were imported into ArcGIS software, allowing for semi-automated counting of nests based on resolved geometry and laser return intensity. Nest resolution and counting accuracy was better than 2%. Spatial analysis of nest locations has established a maximum packing density of 268 nests/m2 in optimum locations, which correspond to roof slopes of >20 degrees. Co-occurring Rhinolophid bats roost adjacent to, but not within nest locations, preferring roof surfaces close to horizontal.
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Detailed geomorphological analysis has revealed that subhorizontal gypsum caves in the Northern Apennines (Italy) cut across bedding planes. These cave levels formed during cold periods with stable river beds, and are coeval with fluvial terraces of rivers that flow perpendicular to the strike of bedding in gypsum monoclines. When rivers entrench, renewed cave formation occurs very rapidly, resulting in the formation of a lower level. River aggradation causes cave alluviation and upward dissolution (paragenesis) in passages nearest to the river beds. The U-Th dating of calcite speleothems provides a minimum age for the formation of the cave passage in which they grew, which in turn provides age control on cave levels. The ages of all speleothems coincide with warmer and wetter periods when CO2 availability in the soils covering these gypsum areas was greater. This climate-driven speleogenetic model of epigenic gypsum caves in moderately to rapidly uplifting areas in temperate regions might be generally applicable to karst systems in different geological and climatic conditions.
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Currently there are many studies focused on the investigation of climatic and glaciological condition of ice caves. Here we present another way to address these studies, applying some methods already used in fields other than geomorphology. The versatility and accuracy provided by the use of modern topography and thermography techniques, using Terrestrial Laser Scanner and current thermographic cameras-and the creation of 3D thermographic models and orthothermographies derived from them - is shown to be a useful tool as it is difficult to obtain data from fieldwork and traditional methods used in caves. This paper presents the potential uses of combined TLS and thermographic techniques for monitoring some important climatological parameters in the sensitive periglacial environment of the Iberian Atlantic high mountains: Pena Castil Ice Cave (Picos de Europa, Northern Spain). A systematic application of such combined technologies to these kind of caves, is expected to contribute to a quantitative and concise characterization of the evolution of the ice as shown by the results of this study.
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The study of karst and its geomorphological structures is important for understanding the relationships between hydrology and climate over geological time. In that context, we conducted a terrestrial laser-scan survey to map geomorphological structures in the karst cave of Algar do Penico in southern Portugal. The point cloud data set obtained was used to generate 3D meshes with different levels of detail, allowing the limitations of mapping capabilities to be explored. In addition to cave mapping, the study focuses on 3D-mesh analysis, including the development of two algorithms for determination of stalactite extremities and contour lines, and on the interactive visualization of 3D meshes on the Web. Data processing and analysis were performed using freely available open-source software. For interactive visualization, we adopted a framework based on Web standards X3D, WebGL, and X3DOM. This solution gives both the general public and researchers access to 3D models and to additional data produced from map tools analyses through a web browser, without the need for plug-ins.
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We present the results of a study of the Vena del Gesso Basin (Romagna Apennines, Italy) integrating field analyses and analogue modelling. This basin represents one of the best-preserved top-thrust basins in the Northern Apennines foreland and is one of the few examples where primary evaporites, related to the Messinian salinity crisis of the Mediterranean, widely crop out. The structural style affecting the Messinian gypsum is examined to get insights into the mechanism responsible for the overall deformation features recognizable in the area. The evaporites are completely detached at the base and widespread back-thrusts, repeatedly doubling these deposits, strongly contrast with the regional forelandward vergence of structures in the Apennines. On the basis of the comparison between field data and experimental results, the features characterising this area can be described as the result of the deformation linked to the sequential activation of an obliquely propagating passive-roof duplex. Analogue models evidenced the major role played (1) by syntectonic erosion that promoted the development of passive-roof duplex style, as well as (2) the role of décollement level pinch-out that determined an oblique progression of deformation. Finally our data lead to reconsider the palaeoenvironmental reconstruction concerning the onset of the Messinian salinity crisis in the Mediterranean. Copyright © 2007 John Wiley & Sons, Ltd.
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We integrate existing and new geologic data [REtreating TRench, Extension, and Accretion Tectonics (RETREAT project)], particularly on the origin, growth, and activity of the mountain front at Bologna, Italy, into a new model that explains Apennine orogenesis in the context of a slab rollback-upper plate retreat process. The Bologna mountain front is an actively growing structure driving rock uplift similar to 1 mm/year, cored by a midcrustal flat-ramp structure that accommodates ongoing shortening driven by Adria subduction at a rate of similar to 2.5 mm/year. The data we use are assembled from river terraces and associated Pleistocene growth strata, geodesy including releveling surveys, reinterpretation of published reflection lines, and a new high-resolution reflection line. These data constrain a simple trishear model that inverts for blind thrust ramp depth, dip, and slip. Apennine extension is recognized both in the foreland, as high-angle normal faults and modest stretching in the carapace of the growing mountain front, and in the hinterland, with larger normal faults that accomplish some crustal thinning as the upper plate retreats. This coevolution of extension and shortening shares some notable characteristics with other basement-involved collisional orogens including the early Tertiary Laramide orogeny in the American West and the Oligocene to Miocene evolution of the Alps. We propose a possible relationship between underplating and the development of the Po as a sag basin as a Quaternary phenomenon that may also apply to past periods of Apennine deformation (Tortonian). Continued shortening on the structure beneath the Bologna mountain front represents by far the most important and underappreciated seismogenic source in the front of the northern Apennines.
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This paper deals with channel evolution over the past 200 yr in 12 selected streams in northern and central Italy and aims at reconstructing the evolutionary trends (e. g., trends of channel width and bed elevation) and understanding the causes of channel adjustments. The selected streams have been studied using various sources and methods (historical maps, aerial photographs, topographic surveys, and geomorphological surveys). The selected rivers have undergone almost the same processes in terms of temporal trends; however, the magnitude of adjustments varies according to several factors, such as original channel morphology. Initially, river channels underwent a long phase of narrowing (up to 80%) and incision (up to 8-10 m), which started at the end of the nineteenth century and was intense from the 1950s to the 1980s. Then, over the last 15-20 yr, channel widening and sedimentation, or bed-level stabilization, have become the dominant processes in most of the rivers. Different human interventions have been identified as the causes of channel adjustments in Italian rivers (sediment mining, channelization, dams, reforestation, and torrent control works). Such interventions have caused a dramatic alteration of the sediment regime, whereas effects on channel-forming discharges have seldom been observed. Some notable implications for river management and restoration are (1) the state of rivers before major human disturbances and channel adjustments can rarely be taken as a reference, as at present rivers are far from their pristine condition; and (2) sediment management is and will be a key issue in such fluvial systems.
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In this paper we propose a new method for the creation of normal maps for recovering the detail on simplified meshes and a set of objective techniques to metrically evaluate the quality of different recovering techniques. The proposed techniques, that automatically produces a normal-map texture for a simple 3D model that "imitates " the high frequency detail originally present in a second, much higher resolution one, is based on the computation of per-texel visibility and self-occlusion information. This information is used to define a point-to-point correspondence between simplified and hires meshes. Moreover, we introduce a number of criteria for measuring the quality (visual or otherwise) of a given mapping method, and provide efficient algorithms to implement them. Lastly, we apply them to rate different mapping methods, including the widely used ones and the new one proposed here.
Book
Book synopsis: This important book brings together eighteen cutting-edge research papers first presented at the Second International Conference on Braided Rivers. It includes the latest research on the dynamics, deposits and ecology of these rivers. Essential reading for geomorphologists, earth scientists, engineers and ecologists with a pure and applied interest in the study, modelling and management of braided rivers.
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Abstract About thirty human footprints made approximately 12,000 years B.P. inside the ‘Sala dei Misteri’ Cave of Básura near Toirano, Liguria, northern Italy, were studied by standard ichnological analysis. Eleven of the best-preserved tracks were examined further using morpho-classificatory and morphometric approaches, in order to estimate the minimum number of trackmakers; biometric measurements were also used to tentatively determine their physical characteristics (e.g., height and age). Results indicate at least three different producers, two youths and the third of tender age. Analysis of the data demonstrate the power of 3D, of landmark-based morphometrics, and the utility of methods of forensic anthropology in the determination of human footprints. The study of the number of trackmakers using the principal component analysis (PCA) on 'multi-trampling' surfaces could represent a model in the ichnological study of cave sites.
Article
Chemical and physical proxy data from a precisely dated early last glacial (~113e110 ka, MIS5d) Sardinian stalagmite reveal a sub-millennial-scale, cool-dry climate event centered at 112.0 þ0.52 /-0.59 ka, followed by a rapid return to warm-wet conditions at 111.76 þ0.43 /-0.45 ka. Comparison with regional speleothem records and the palaeotemperature proxy record from the NGRIP ice core (Greenland) suggests that this event corresponds to Greenland Interstadial (GI) 25b and 25a, an intra-interstadial climate oscillation within GI-25, according to the recent Greenland stratigraphic framework. The speleothem age is in reasonable agreement (within 0.8 kyr) with that of the corresponding event in Greenland based on the GICC05modelext ice chronology but is older by about 3.7 kyr than the Greenland age based on the AICC2012 chronology.
Article
Terrestrial laser scanning (TLS) is increasingly used in geomorphology for the study of medium- to small scale landforms. A light weight, compact and portable TLS device has been used in the Grotta A Cave (Mt. Lessini, N Italy) to make a detailed 3D model of the underground environment. A total of 16 scans were used to survey the about 150 m long cave in less than 6 hours. The 3D model of the cave walls makes it possible to carry out morphometric measurements on the different cave environments. The TLS data allowed us to calculate cave volumes and distinguish cupola, phreatic conduit and basalt dike volumes. Wall roughness analysis also allowed recognising smaller-scale morphologies such as megascallops, differential corrosion forms and mineral crusts. These observations have enabled us to discern between different karstification processes and speleogenetic phases, highlighting the importance of condensation-corrosion on the cave passages enlargement in a quantitative way.
Article
Inactive swallow hole Buco dei Vinchi developed along a plane dividing selenitic gypsum stratum and an underlying shale interlayer, mostly by antigravitative erosion and by post-antigravitative erosion. It formed through six speleogenetic phases starting from a phreatic phase followed by several antigravitative erosion (= paragenetic) and post-antigravitative erosion phases and vadose phase. During first antigravitative erosion phase, the phreatic protoconduits evolved into small antigravitative conduits with typical cross-section in shape of an inversed U or a bulb. At the end of this phase the small antigravitative conduits converged and merged together in successive stages to form ever-bigger conduits, until - at a certain point - most of them flowed into a single, much wider antigravitative conduit, which later evolved into a composite conduit. We demonstrate that the subhorizontal flat ceilings are not a characteristic feature of the antigravitative passages tout court - as claimed by most authors -, but instead they evolved in caves during periods when the piezometric surface was tangent to the vault of the cave (post-antigravitative erosion phenomenon). Thus these flat ceilings are traces of 'paleo-piezometric surfaces'; moreover these flat ceilings, being sub-horizontal originally, can provide important information on possible tectonic movements or breakdowns occurred after their formation. The possible ages of the karstic phenomena in the selenitic gypsum near Bologna are discussed. This paper points out that the Buco dei Vinchi and the Cava a Filo swallow holes, presently located in "topographic highs", were very probably in "topographic lows" at the time of their hydrologic activity, and that this is evidence of a relief inversion started at least 127,000 years ago. Therefore the beginning of the first karstic phenomena in the Bologna karst area is much older than this date. It is explained why the absolute altimetrical lowering of the Monte Croara karst sub-area (with respect to the present sea level) should be of about - 0.39 mm/year.
Article
This article provides an overview of the various digital tools we have used and developed to study and promote a range of karst geosites. Our work focused on the very high heritage value endokarst sites (caves or karst networks) in France’s Ardèche département (Chauvet Cave, Aven d’Orgnac) and Chartreuse (Granier cave network), Vercors (Choranche Caves) and Bauges (Prérouge Cave) Regional Parks. These tools were developed using innovative, high-tech digital monitoring and 3D modelling technologies and combined laser scanners, digital cameras and sensors with specialised software. The resulting tools are now being used in the management and promotion of these sites, which are important territorial and heritage resources in areas where geotourism is increasing and being integrated into local planning strategies.
Article
The present work deals with the results of long-term micro-erosion measurements in the most important gypsum cave of Spain, the Cueva del Agua (Sorbas, Almeria, SE Spain). Nineteen MEM stations were positioned in 1992 in a wide range of morphological and environmental settings (gypsum floors and walls, carbonate speleothems, dry conduits and vadose passages) inside and outside the cave, on gypsum and carbonate bedrocks and exposed to variable degree of humidity, different air flow and hydrodynamic conditions. Four different sets of stations have been investigated: (1) the main cave entrance (Las Viñicas spring); (2) the main river passage; (3) the abandoned Laboratory tunnel; and (4) the external gypsum surface. Data over a period of about 18 years are available. The average lowering rates vary from 0.014 and 0.016 mm yr-1 near the main entrance and in the Laboratory tunnel, to 0.022 mm yr-1 on gypsum floors and 0.028 mm yr-1 on carbonate flowstones. The denudation data from the external gypsum stations are quite regular with a rate of 0.170 mm yr-1. The observations allowed the collecting of important information concerning the feeding of the karst aquifer not only by infiltrating rain water, but under present climate conditions also by water condensation of moist air flow. This contribution to the overall karst processes in the Cueva del Agua basin represents over 20% of the total chemical dissolution of the karst area and more than 50% of the speleogenetically removed gypsum in the cave system, thus representing all but a secondary role in speleogenesis. Condensation-corrosion is most active along the medium walls, being slower at the roof and almost absent close to the floor. This creates typical corrosion morphologies such as cupola, while gypsum flowers develop where evaporation dominates. This approach also shows quantitatively the morphological implications of condensation-corrosion processes in gypsum karst systems in arid zones, responsible for an average surface lowering of 0.047 mm yr-1, while mechanical erosion produces a lowering of 0.123 mm yr-1.
Article
The karst of Sorbas (SE Spain) is one of the most important gypsum areas worldwide. Its underground karst network comprises over 100 km of cave passages. Rounded smooth forms, condensation cupola and pendant-like features appear on the ceiling of the shallower passages as a result of gypsum dissolution by condensation water. Meanwhile, gypsum speleothems formed by capillarity, evaporation and aerosol deposition such as coralloids, gypsum crusts and rims are frequently observed closer to the passages floors. The role of condensation-dissolution mechanisms in the evolution of geomorphological features observed in the upper cave levels has been studied by means of long-term Micro-Erosion Meter (MEM) measurements, direct collection and analysis of condensation waters, and micrometeorological monitoring. Monitoring of erosion at different heights on gypsum walls of the Cueva del Agua reveals that the gypsum surface retreated up to 0.033 mm yr-1 in MEM stations located in the higher parts of the cave walls. The surface retreat was negligible at the lowest sites, suggesting higher dissolution rates close to the cave ceiling, where warmer and moister air flows. Monitoring of microclimatic parameters and direct measurements of condensation water were performed in the Covadura Cave system in order to estimate seasonal patterns of condensation. Direct measurements of condensation water dripping from a metal plate placed in the central part of the El Bosque Gallery of Covadura Cave indicate that condensation takes place mainly between July and November in coincidence with rainless periods. The estimated gypsum surface lowering due to this condensation water is 0.0026 mm yr-1. Microclimatic monitoring in the same area shows differences in air temperature and humidity of the lower parts of the galleries (colder and drier) with respect to the cave ceiling (warmer and wetter). This thermal sedimentation controls the intensity of the condensation-evaporation mechanisms at different heights in the cave.
Article
The gypsum karst of Sorbas is developed within Messinian gypsum characterized by an interbedded sequence of selenitic gypsum beds and marls. This geological configuration has led to the development of an interstratal karst in which galleries have developed in the marl levels, but not in the gypsum ones. Up to six cave passage levels have been detected in the gypsum caves following stratification planes between the impervious intercalated marls and the pervious gypsum strata. The explanation for this lies in the hydrogeological history of the area. Initially, the gypsum karst evolved as a multi-layer, semi-confined aquifer under phreatic conditions, enabling the formation of small proto-conduits in the individual gypsum beds, while the intervening marls and clays acted as impervious barriers. During a second stage, after lowering of the piezometric level, vadose conditions were established in which mechanical erosion processes in the intercalated marls and clays became predominant. This genetic duality means that the gypsum karst at Sorbas can be taken as an example of interstratal karstification where the contemporary underground erosion processes and those of karstic evolution should be considered products of the hydrogeological development. The total lowering of the piezometric level during the Quaternary is at least of 120 m in the centre of the basin. Interstratal vadose caves more than 120 m below the surface possess phreatic proto-channels in their upper levels which identify the past phreatic conditions in the genesis of the caves.
Article
Erosion, river incision, and uplift rates in the northern andcentral Apennines, Italy, since 0.9 Ma, are determined fromnew cosmogenic nuclide data. Beryllium-10 concentrations inmodern and middle Pleistocene sediments indicate erosion ratesfrom 0.20 to 0.58 mm/yr. These rates are similar to estimatesof sediment yield (0.12-0.44 mm/yr), river incision (0.35mm/yr), and uplift (0.01-1.0 mm/yr) rates inferred fromother methods that integrate landscape process rates since theearly Pleistocene. These rates of landscape change are significantlylower than long-term exhumation rates of 1.2 mm/yr since ca.4.5 Ma, inferred from thermochronometry. Collectively, thesedata suggest that hillslope erosion and river incision ratesin the northern and central Apennines have balanced local upliftrates for 1 My, but that exhumation rates have slowed significantlysince emergence of the mountain chain in the Pliocene. Thiscondition of dynamic equilibrium was potentially achieved withinca. 3 Ma, similar to some model predictions of hillslope andfluvial system adjustment.
Article
The Messinian Vena del Gesso Basin in the Northern Apennines is filled by very thick (up to 35 m) beds of coarse crystalline gypsum (selenite) associated with thinner carbonate and shaly (euxinic) intercalations. The conventional Usiglio model of salt fractionation does not apply to this evaporitic sequence for the following reasons: carbonate which underlies gypsum is not evaporitic but algal in origin; most gypsum did not precipitate from surface brines but at and below a sediment-water interface occupied by algal mats; a significant portion (10–80%) of gypsum beds is composed of redeposited selenite which was removed from the margins and transported toward the centre of the basin by slope-controlled currents and gravity flows (debris flows).We call this process cannibalistic because of its intraformational character (connected with evaporative fall of water level) and volumetric importance.A recurrent vertical pattern of six main facies (euxinic to gypsum fanglo-merates) is interpreted as a bathymetric, regressive cycle controlled by both sedi-mentological and tectonic-eustatic factors. The inferred environmental setting is a residual turbidite trough (Marnoso-arenacea) evolving abruptly toward lagoonal conditions and filled up to sea level by evaporitic and mechanical (mostly fluvial) processes. Repeated inundations of restricted-marine water started the depositional cycle thirteen or fourteen times.
Article
The detailed survey of surfaces, such as are found in caves, buildings or excavation sections, is an important aspect of archaeological data collection and investigation. Where subtle irregularities of the contours of the surface have a significance to the interpretation of an archaeological feature, and where contact with the surface is not recommended, standard surveying techniques may not provide the resolution or accuracy which might be hoped for. This study uses an automated laser scanner and modelling software to produce an accurate three-dimensional model of a carved rock surface from the Upper Palaeolithic site of Cap Blanc in southwest France. This non-invasive procedure provides a means of documenting and visualizing a complex carving, and therefore contributes to the interpretation and archiving of the site.
Article
Graphic and metric archaeological documentation is an activity that requires the capture of information from different sources, accurate processing and comprehensive analysis. If monitoring of the state of conservation is required, this task has to be performed before intervention, during and after the completion of the works in a repetitive way.This paper presents the use of terrestrial laser scanning (TLS) in order to effectively produce, prior to intervention, accurate and high-resolution 3D models of a cave with engravings dating back to the Upper Palaeolithic era. The processing of the TLS data is discussed in detail in order to create digital surface models. The complexity of the cave required the integration of two techniques, TLS and close range photogrammetry to yield not only traditional drawings such as sections and elevations, but also photo-realistic perspective views and visual navigation worlds fully operational in 3D environments. This paper demonstrates the potential of integrating TLS and close range photogrammetry to provide both accurate digital surface models and photo-realistic outputs. This processed data can be used to systematically improve archaeological understanding of complex caves and relief panels of prehistoric art with tiny engravings.
Article
In the speleological literature three terms are utilized to designate the “ascending erosion”: paragenesis (= paragénésis, coined in1968), antigravitative erosion (= erosione antigravitativa, coined in 1966) and antigravitational erosion (wrong English translation ofthe Italian term erosione antigravitativa, utilized later on). The term paragenesis should be abandoned because of the priority of theterm erosione antigravitativa - on the ground of the “law of priority” – and because of its ambiguous etimology. On the other hand,the term antigravitational erosion should be forsaken in favour of the term antigravitative erosion, given the meaning that the termsgravitation and gravity have in Physics. Therefore, to designate the phenomenon of the “ascending erosion” there would be nothingleft but the term antigravitative erosion.The antigravitative erosion process and its recognizability are illustrated.Examples of caves with evident antigravitative erosion phenomena, developed in different karstifiable rocks and in several partsof the world, are given.It is recalled that the antigravitative erosion is a phenomenon well-known since 1942 and widely proven and supported, and that it isrelatively easy – in many cases - to recognize the antigravitative origin of karstic passages.It is stressed that the antigravitative erosion is an important phenomenon, exclusive of the karstic caves and unique in nature.
Speleogenesis in noncarbonate lithologies
  • A B Klimchouk
Klimchouk, A.B., 2000. Speleogenesis in noncarbonate lithologies. In: Klimchouk, A.B., Ford, D.C., Palmer, A.N., Dreybrodt, W. (Eds.), Speleogenesis, Evolution of Karst Aquifers. National Speleological Society, Huntsville, pp. 430-442.
Analisi di facies e macrotettonica della Vena del Gesso in Romagna
  • S Marabini
  • G B Vai
Marabini, S., Vai, G.B., 1985. Analisi di facies e macrotettonica della Vena del Gesso in Romagna. Boll. Soc. Geol. Ital. 104, 21-42.
Cave Geology. Cave books
  • A N Palmer
Palmer, A.N., 2007. Cave Geology. Cave books, Dayton, OH.
Visibility based methods and assessment for detailrecovery
  • M Tarini
  • P Cignoni
  • R Scopigno
Tarini, M., Cignoni, P., Scopigno, R., 2003. Visibility based methods and assessment for detailrecovery. In: Proceedings of the IEEE Visualization Conference. IEEE, 457-464.
Efficient high quality rendering of point sampled geometry
  • M Botsch
  • A Wiratanaya
  • L Kobbelt
Botsch, M., Wiratanaya, A., Kobbelt, L., 2002. Efficient high quality rendering of point sampled geometry. Proceedings of the 13th Eurographic workshop on Rendering (12 p).
Therion -digital cave maps
  • M Budaj
  • S Mudrák
Budaj, M., Mudrák, S., 2008. Therion -digital cave maps. Spelunca Mémoires. 33, pp. 138-141.
FARO® Laser Scanner Focus3D Manual
  • Faro
FARO, 2011. FARO® Laser Scanner Focus3D Manual. October 2011. pp. 40-51.