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Integration of MIVIS Hyperspectral remotely sensed data and Geographical Information Systems to study ancient landscape: the Aquileia case study

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A large number of technologies, such as Geographic Information Systems (GIS), Global Positioning Systems (GPS), Remote Sensing (RS), geophysical instruments, allows nowadays for fast and reliable automated capture, management and analysis of archaeological data. Beyond the City Walls (BCW) is a landscape archaeology project based in the countryside of the Roman municipium of Aquileia (Italy) that applies and integrates these technologies for the reconstruction of peripheral settlement dynamics in antiquity, trialling concurrently tools that operate as hubs for acquisition of disparate field data.
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Integrated Archaeological Investigations
for the Study of the Greater Aquileia Area
Arianna Traviglia
Department of Ancient History, W6A 338 Macquarie University,
NSW 2019, Australia
arianna.traviglia@mq.edu.au
Abstract. A large number of technologies, such as Geographic Information
Systems (GIS), Global Positioning Systems (GPS), Remote Sensing (RS),
geophysical instruments, allows nowadays for fast and reliable automated
capture, management and analysis of archaeological data. Beyond the City Walls
(BCW) is a landscape archaeology project based in the countryside of the Roman
municipium of Aquileia (Italy) that applies and integrates these technologies for the
reconstruction of peripheral settlement dynamics in antiquity, trialling concurrently
tools that operate as hubs for acquisition of disparate field data.
Keywords: Archaeological remote sensing, Aerial photography, Multispectral
and hyperspectral data, Historical maps image processing, GIS, GPS.
1 Introduction
From its „official‟ inception in the second part of the 19th century, the archaeological
research on Aquileia has mainly concentrated on the analysis of building and planning
aspects of the Roman city, focussing on issues related to the urban sector [1-3]. The
surrounding countryside has by comparison received little consideration, with just a
limited number of projects focussed on the reconstruction of the suburban settlement
system, or the functional distribution of suburban spaces being performed during the last
decades [4-8]. The systematic detection of the landscape spatial organisation using
remotely-sensed data and topographic survey has been scarcely undertaken in the area,
and where this has occurred it has not been followed by consistent ground-testing to
verify the nature and scope of the detected traces. These attempts were based in turn
either on aerial photography [9] and multi and hyperspectral data [10-13]; however, some
of these pioneering efforts in remote sensing-based landscape reconstructions have not
always found complete support within the archaeological discourses [5].
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1.1 Beyond the city walls
Against this background, the „Beyond the City Walls (BCW): the landscapes of Aquileia‟
project1 aims to provide a timely study of Aquileian landscapes to understand trends of
peripheral occupation at different scales and times.
The study seeks to illuminate the landscape settlement dynamics of Aquileia‟s
periphery in antiquity, as seen through the layers of subsequent reorganisation of the land,
and to re-orient the discussion from an exclusive focus on the city to a broader
understanding of the city‟s relationship with the periphery and surrounding landscape.
These goals are being pursued using a combination of traditional archaeological research
together with a flexible data modelling system, automated data collection in the field and
the employment of geomatics (including the use of Geographic Information Systems
(GIS), multi and hyper-spectral remote sensing, and geophysical methods). Remote
sensing plays here a fundamental role in the identification of the Roman spatial signature
on the Aquileian landscape, contributing efficiently in the detection of the elements of the
built and natural environments that are constituents of the past landscape.
1.2 The case study area
The BCW project includes a vast portion of the peripheral territory of Aquileia, namely
the Communes of Aquileia,
Terzo di Aquileia, Fiumicello, Villa Vicentina, Cervignano,
Grado, Marano Lagunare, Ruda, Torviscosa, and Turriaco (Fig.1). To properly assess the
dynamics of landscape transformation, large areas and multiple locations need in fact to be
holistically investigated. Examination of a single location, unrelated to its broader
landscape and cultural context, would provide only a limited view of the functional
characteristics of the investigated landscape.
The area, ranging from a coastal tract to a primarily flat, fertile plain, was altered in the
past by geomorphic processes related to rising sea levels [14] and the migration of rivers
[15] as well as human-induced change.
1 BCW is a Macquarie University (Sydney, Australia) research project directed by the Author
and performed in collaboration with the Superintendence of the Archaeological Heritage of Friuli
Venezia Giulia.
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Fig. 1. The extent of the case study area.
2 Sensing the Aquileian landscapes
Remote sensing in landscape studies holds a key role in the identification of data on the
ground that is unobtainable using traditional archaeological fieldwork techniques. The
imagery has the potential not only to disclose a substantial amount of information related
to isolated anthropogenic features but also to elucidate landscape transformations
connected to ancient human modifications of the environment.
Multi-sourced and multi-temporal remote sensing imagery coverage is needed in order
to collect as much information as possible in relation to a territory that has undergone
major transformations in the past 80 years. For this reason a large acquisition campaign
has been undertaken resulting, at the current state of research, in a holding of around 350
images, whose number increases exponentially once we consider the processed images2.
Aerial, multi and hyperspectral data are included in this material. In addition, digital
topographic data from radar systems (Shuttle Radar Topography Mission -SRTM-) and
satellite-borne sensors (Advanced Spaceborne Thermal Emission and Reflection
Radiometer -ASTER- GDEM) have been acquired to be used as reference datasets in the
interpretive process.
2.1 The remote sensing imagery
Aerial photos. A vast survey of available past and recent aerial photographs has been
undertaken (and is still in progress) in several regional and national institutions to achieve
the most comprehensive coverage of the investigated area and provide a wide temporal
span. The available imagery includes historical and modern photos spanning from vertical
photos dated 1938 to recent orthophotos dated 2007, with an average of at least one aerial
2 Each image can in fact undergo up to 10 or more different processes creating new imagery that
requires separate examination [18].
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coverage every ten years. Historical photos3 hold an incredible documentary value since
they document the state of the Aquileian landscape in a period preceding the massive
reclamation works started in 1933. It is therefore a straightforward procedure to detect
anthropogenic features, land partitions and outdated tracks that are no longer traceable in
the current territorial configuration.
Modern aerials4 (Fig. 2) provide important insights into the transformation of the
territory and are a vital reference for identifying recent traces of territorial changes that
may be easily mistaken as ancient.
Fig. 2. Geo-referenced aerial photos (CGRA 1990 left, IGM 1984 right).
Multispectral and hyperspectral data. The current provision of multi- and
hyperspectral data includes Landsat TM5, ASTER, GeoEye Ikonos and Daedalus
Multispectral Infrared and Visible imaging Spectrometer (MIVIS) imagery, with GeoEye
GeoEye-1 and DigitalGlobe Quickbird in the process of acquisition. While the poor
resolution of Landsat TM and ASTER (respectively 30m and 15/30/90m according to the
band) make them mainly suitable for detection of broad environmental features, MIVIS
and Ikonos (with a surface resolution respectively of 3m and 4m -multispectral-) are
demonstrably effective in the remote recognition of anthropogenic and natural traces of
medium-small size, having a minimum average area of 40m2 or a length of at least 15/20m
(Fig. 3). MIVIS and Ikonos resolution is limited in comparison to some of the latest HR
multispectral products, such as Quickbird and GeoEye-1, but the amplitude of the portions
of the electromagnetic spectrum they cover (especially with regard to the IR band) makes
them highly suitable imagery for archaeological goals.
3 The holding includes IGM (Military Geographic Institute) coverage from 1938, 1945, 1954.
4 Modern aerials include IGM coverage from 1974 and 1984, CGRA (Compagnia Generale Riprese
Aeree, Parma) coverages from 1990 and Orthophotos from 2000, 2003, 2007.
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Fig. 3. Linear traces evident on a TC display of a MIVIS run, located east of the Aquileia Circus [18]
DEM data. In order to define an objective framework for assessing the interpretations of
traces, a SRTM3 DEM (90 m nominal resolution) and a ASTER GDEM (30 m nominal
resolution) are systematically being used as a reference dataset and compared to the
remotely sensed data, providing important information that contributes to a better
understanding of the feature patterns.
2.2 Image processing
Image processing of remote sensing data is a fundamental step in the enhancement of the
visibility of traces. The goal of the enhancement techniques is to increase and improve the
optical distinction between features and traces recorded in the scene by generating a new
image where the useful information is more easily detectable and measurable.
Currently 1/3 of the acquired aerial images have been already processed for routine
image restoration and enhancement5 as well as ortho-rectified and geo-referenced, while
the completion of the procedure is expected by the end of the year.
A vast range of procedures has been applied to multi and hyperspectral imagery
according to the type of environmental settings represented in each image or in portions of
it. Among them, Vegetation Indices (VI), Principal Components Analysis (PCA) and Soil
Line Index (SLI) have proved to be extremely useful to augment the visibility and
definition of traces.
Vegetation Indices. Vegetation indices provide critical information of variability in the
amount, development and vigour of vegetation, and have thus proven extremely valuable
in archaeological research for detecting natural and archaeological deposits that augment
or limit the growth of the plants [16-17]. The presence of extraneous elements (such as
construction debris) in the composition of the subsoil can have a strong impact on the
growth of the vegetation, determining the manifestation of “marks” over the vegetation.
5 Image enhancement of aerial includes common procedures such as contrast enhancement,
histogram equalisation, interactive grey-level slicing (thresholding).
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The vegetation becomes, in this way, the mediating element of the subsurface
heterogeneity.
Vegetation Indices are particularly efficient when computed over hyperspectral data,
such as MIVIS, due to their fine quantisation of spectral information, which allows for
accurate definition of absorption features. As part of the standard procedure of VIs
application to the MIVIS data available for Aquileia, an average of 5 to 7 different VIs
have been trialled [18] on each MIVIS scene, including indexes like DVI, NDVI,
MSAVI26. As a result, a substantial number of potential archaeological features, made
visible through alteration over the vegetation, have been identified and mapped (Fig. 4).
Fig. 4. The use of MSAVI2 (right) allows for visualising linear traces that are not visible in the
True colour (left) MIVIS data.
PCA and Selective PCA. Principal Component Analysis has found substantial usage in
archaeological research since it can improve the differentiation of dissimilar surfaces,
landform and geomorphic features, which thus become more distinguishable during visual
inspection. PC transformation is particularly suitable for MIVIS hyperspectral data since
starting from MIVIS original and redundant 102 bands it generates a new, limited series of
bands (the Principal Components), where the information content is concentrated. The
transformed bands can then be used for visual analysis in lieu of the original, numerous
MIVIS bands. Principal Components 1, 2 and 3 of MIVIS data have demonstrated to hold
virtually all of the variance in the scene (on average 99.6 %) and, as a consequence, of the
6 Difference Vegetation Index (DVI) is a subtraction operation involving Red and NIR pixel values:
DVI=NIR-R; RVI [19]; Normalized Difference Vegetation Index (NDVI) is the difference of the
Red and Near Infrared band combination divided by the sum of the Red and Near Infrared band
combination: NDVI = (NIR Red )/(NIR + Red) [20]; 2nd Modified Soil Adjusted Vegetation Index
(MSAVI2) is a recursion of MSAVI: MSAVI2 = (1/2)*[2(NIR+1) - (2(NIR+1) 2- 8(NIR- Red)]
[21]. See [22] for a discussion on their application to archaeological contexts.
Integrated Archaeological Investigations… C-7
total information, although valuable information can occasionally be found in higher-order
Principal Components [22].
To overcome the inevitable loss of details entailed in the PCA7, a SPCA (Selective
Principal Components Analysis), which is a PCA computed for groups of bands belonging
the same spectral region or to a single spectrometer of the sensor, is routinely applied to
Aquileia's MIVIS scenes and Selected Components are then displayed in composites
using a dedicated correlation matrix in order to identify the minimum set of SPCs able to
provide most complete information [22].
Soil Line Index. A Soil Line Index was defined to provide support in the identification of
archaeological traces on bare soil using MIVIS data [23]. The SLI produces a new image
where the optical distinction between the wetness or the dryness of the top soil is
increased. By accentuating the dry-wet discrimination, the index facilitated the distinction
of linear or areal features from the surrounding ground.
2.3 From remote sensing to remote mapping
Raw and processed RS datasets are being managed into a GIS environment. The remotely
sensed traces holding an archaeological potential identified on the processed images are
converted to vector coverage. The process is accomplished via heads-up digitising, tracing
on-screen the outlines of traces deemed to have an archaeological interest. The detected
anthropogenic features and the topographical anomalies are being mapped at a nominal
scale of 1:1000 and being given a series of attributes to encapsulate pertinent information.
Among the attributes being retained in this process are metadata about the image
process(es) that facilitated identification, the degree of visibility of the trace, the likely
interpretation of the feature and the photo-interpretation factor (dimension, alignment,
orientation, shape, texture, pattern, size) which supported its detection.
At the current state of advancement, over 700 features have been identified and tagged
(Fig.5) using less than 1/3 of the available imagery. The identified features concur to
create a preliminary repository map, which is then tested by contrasting the mapped traces
against available datasets (see par. 3) suitable for the trace validation process. Experience
shows that a high number of these features will be discounted when contrasted with those
ancillary data as well as during and after the ground check. The trace crosscheck
procedure is one of the steps for the creation of a final „Map repository of remotely sensed
anthropogenic traces‟.
7 Many details that are visible when analysing the original separate bands cannot always be
recognised in the PCs because they are concealed by the overlaying information from other bands.
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Fig. 5. Detail of remotely detected traces plotted against Aquileian ancient topography (modern
topography in background). In this visualisation, they are colour coded based on their visibility.
3 Assessing the image detection procedure
One of the most challenging steps of every remote sensing project is the trace assessment
and substantiation i.e. the procedure of validating through auxiliary datasets the traces,
features and anomalies detected during the visual analysis of remote sensing imagery.
Although ground truthing activities for verification of remotely obtained trace datasets
(see below par. 4) assume vast relevance, the constant cross-reference to ancillary datasets
(cartographic -modern and historical-, archival, archaeological) is an essential stage of the
process of validation or discounting of the detected traces, reducing time consumption
during the interpretation process and providing the basis for a prioritised strategy of
ground verification.
3.1 A GIS for the Aquileian territory
The BCW GIS (©ESRI ArcGIS 10) manages a vast range of pre-existing topographical
and cultural datasets as well as project generated survey and remote sensing datasets that
concur to build an understanding of the landscape transformation. The datasets
incorporate modern geospatial information, historical mapping, archaeological and
cultural records.
Contrasted against these comprehensive data assets, the traces repository map can be
refined by assigning each feature a value of „archaeological reliability‟ [18, 22], i.e. an
evaluation (expressed as a percentile) of the potential of such feature to have an
archaeological nature.
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3.2 Modern cartography
The Region Friuli Venezia Giulia holds a substantial asset of digital cartography including
a complete regional digital coverage in scale 1:5000 and 1:250008. The available coverage
serves as a topographical base layer both for mapping features and surveying activities on
the field, providing a high level of detail and accuracy as well as constant update.
Pre-digital cartographic materials, produced between 1970 and 1990, have been
likewise acquired by scanning and geo-referencing them, since they retain a significant
number of useful information related to landscape changes that occurred in recent times.9
A vast assortment of thematic maps10 are also available to the project, making available
a substantial body of environmental information supporting the reconstruction of the past
landscape evolution.
3.3 Historical cartography
The Aquileian landscape is depicted in a large number of small and large-scale historical
maps from a period spanning nearly 400 years. Such documentation provides key insights
on landscapes arrangements, changing settlement patterns, and landscape elements
preserving relics of ancient activities.
Historical maps have been -and are still being-collected from regional and national
archives11. Currently approximately 90 maps representing the Aquileian countryside and
the peri-urban area, have been identified suitable for this project. A systematic semantic
and conceptual analysis, for the purpose of data modelling, is being conducted on the
already acquired maps. As part of their acquisition in the data modelling system, all the
maps undergo geo-referencing procedure, although many of the earliest ones exhibit
planometric distortions that make them too complex to use directly (Fig. 6). To overcome
this deficiency, the maps are processed manually after the geo-referencing in order to map
elements that provide insight on the settlement dynamics and at the time of their drafting.
This procedure captures nearly all map-specific information, and is well suited for data
mining and more sophisticated visualisations of the results.
8 A 1:10000 scale coverage, obtained through photo-reduction of the 1:5000 coverage, is also
available.
9 A primary use is the fact that the orientation of the irrigation ditches can be and often has been
changed in past decades. These previous water channels are clearly visible in remote sensing
imagery and can easily been mistaken for centuriation markers or other ancient features.
10 The collection includes the Geologic Map of Friuli Venezia Giulia (scale 1:150.000), and the
Technical-Geological Map (scale 1:5.000) incorporating the Geomorphological Map, the Subsoil
Map, and the Structural Map.
11 Namely the State Archives of Triest, Venice and Gorizia, the Capitolo Archive of Udine, the
Provincial Archive of Gorizia and a number of libraries, including the Biblioteca Joppi of Udine,
the Biblioteca Statale Isontina of Gorizia and the Marciana National Library of Venice.
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Fig. 6. A Napoleonic Cadastral map (1811) geo-referenced against the modern topographic maps.
On the right: the zoom shows the Napoleonic map plotted against the modern topographic map.
3.4 Archaeological and cultural datasets
A comprehensive archaeological map in vector format of the Aquileian countryside
has been created by digitisation of published archaeological cartography12 and a
systematic collection and plotting of archaeological literature. Location of past casual
finds, excavations, and surveys have been recorded with the best possible level of
accuracy, although this was not always achievable in reference to decades old
information. The inclusive map supplies contextualisation for remote sensing and
survey obtained data as well as historical mapping datasets, allowing comparison with
the elements that compose the past landscape and their interpretation.
4 Ground truth activities
A critical part of any archaeological application of remote sensing is the fieldwork
component of the project. A large number of cross tests assists in the verification of
identified traces and the quality control of image processing techniques, with field walking
survey and use of geophysics instrumentation underpinning the substantiation of the
ground mapped features.
At the current state of the research the prospective archaeological sites are inspected
through systematic field walking survey. In a future stage of the project, the sites with the
highest archaeological reliability will be investigated through geophysical methods,
namely Ground Penetrating Radar and Electromagnetic survey.
These ground-based methods will support the verification of underground
archaeological deposits and will eventually result in the collection of detailed physical
dimensions of the detected features.
12 Archaeological map holdings include [1, 24]. Archaeological maps from 18th and 19th centuries
(such as the ones realised from G.D. Bertoli, C. Baubela, E. Maionica and P. Kandler) are
included in the historical cartographic dataset.
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4.1 Ground survey
Field survey is being carried out following conventional procedure of field-walking in
(virtual) grids or line transects, subject to the consent of the local landowners. Current
verifications are being conducted in March-April and October-November periods, with
repetition of ground-truthing activities at the same location, in order to ensure systematic
coverage over the investigated areas and possibility of better visibility of detected features
in dissimilar environmental, climatic and seasonal conditions.
The survey activities include differential GPS recordings of transects/grids and on
surface visible features, in addition to documentation of surface artefacts using mobile
devices by systematically mapping the density distribution of artefacts and their spatial
variability. Fieldwork relies heavily on automated procedures of mobile data recording
because of a number of practical issues related to fast data collection, connected to the
opportunity to access large fields only for limited periods.
Fieldwalker App. Fieldwalker is a custom-made Android App developed for this
project in order to speed up the field data collection. The App runs on a Samsung Galaxy
tablet and is remotely connected via Wi-fi to the GPS to receive positioning and geo-
locate field-recorded data in real time. By entering the relative positions of the surveyors
and tracking the walking path via GPS, it is possible to store textual, photographic and
graphic information on the field for each positions of the surveyors. The App also works
in fact as a hub for automated acquisitions of geo-located photo shots on the field and
manual drawing. Although mobile GIS products are commercially available, the App
expands considerably the capabilities of those products providing more flexibility and
customisation, and the possibility to import disparate types of data.
5 Forthcoming research
The BCW project is currently at its first stage, with three complete field campaigns and
two per year, planned for the next years. As a result of the preliminary ground
verifications, a number of sites holding a very high archaeological potential have been
identified and will be further investigated using non-invasive geophysics methods.
Indicators of past human presence and activities, such as potsherds and other surface
artefacts, are being identified, counted, sampled and plotted against the topography of the
investigated areas. The count data collected on the field are being used for the creation of
distribution and density maps (Fig. 7) of archaeological deposits on the plough soil
surface. One of the current focuses is to distinguish assemblages that reflect the
anthropogenic use of the site, from others that are just the results of different
interventions, such as, for example, the terrain transfer from one location of the Aquileian
countryside to another site, a common practise adopted in the area until fairly recent times
as part of reclaiming the land. The goal is being pursued by the analysis of soils on which
the artefacts are deposited. At the current stage of results, it appears sufficiently clear that
the original stratigraphy in sections of the territory S of the Aquileia have been heavily
reworked and altered, and that natural phenomena contributed to significantly modify the
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original deposits. Notwithstanding it is still possible to identify portions of agricultural
fields, where later modifications have not changed the surface sites in a substantial way
(both manifestations of covered strata or phenomena existing only on the present surface
with no relationship to a stratified deposit), that retain substantial evidence of spatial
distribution created by past cultural activities. The prosecution and widening of this study
of high-density and low-density artefact scatters, preserving information about past human
activities, will provide in turn a better understanding of the settlement dynamics and land
management of the Aquileian landscapes.
Fig. 7. Distribution and density of artefacts on the ploughsoil surface (M. Chang).
Acknowledgments. The author wishes to thank the Servizio pianificazione
territoriale‟ of Regione Friuli Venezia Giulia, the Consorzio di Bonifica Bassa
Friulana, the Arts eResearch at The University of Sydney, Mr D. Busato, Dr M.
Chang and all the students and volunteers participating to the 2010 and 2011 surveys.
Special thanks also to Soprintendenza Archeologica del Friuli Venezia Giulia and the
National Museum of Aquileia, in the persons of Dr L. Fozzati, Dr M. Novello and Dr
P. Ventura, for their kind support and assistance.
Regione Friuli Venezia Giulia data authorisation: P.M.T./1295/2100, 25-01-05.
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... AIS is typically used to image entire areas without having geographical data gaps. So far, AIS has been used in several archaeological projects, for example [150,[155][156][157][158][159][160][161][162][163][164][165][166][167][168]. The success rate regarding archaeological subsurface structure detection is, however, variable and less effective applications seem to be connected with the lower spatial resolutions of the acquired datasets (in most cases the GSD ranges from 1 m to 4 m). ...
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Archaeologists often rely on passive airborne optical remote sensing to deliver some of the core data for (European) landscape archaeology projects. Despite the many technological and theoretical evolutions that have characterised this field of archaeology, the dominant aerial photographic surveys, but also less common approaches to archaeological airborne reconnaissance, still suffer from many inherent biases imposed by sub-par sampling strategies, cost, instrument availability and post-processing issues. This paper starts with the concept of landscape (archaeology) and uses it to frame archaeological airborne remote sensing. After introducing the need for bias reduction when sampling an already distorted archaeological population and expanding on the ‘theory-neutral’ claim of aerial survey, the paper presents eight key characteristics that all have the potential to increase or decrease the subjectivity and bias when collecting airborne optical imagery with passive sensors. Within this setting, the paper then offers some technological-methodological reflection on the various passive airborne optical imaging solutions that landscape archaeology has come to rely upon in the past decades. In doing so, it calls into question the effectiveness and suitability of these highly subjective approaches for landscape archaeology. Finally, the paper proposes a new, more objective approach to aerial optical image acquisition with passive sensors. In the discussion, the text argues that the suggested exhaustive (or total) airborne sampling of the preserved archaeological record might transcend particular theoretical paradigms, while the data generated could span various interpretational perspectives and oppositional analytical approaches in landscape archaeology.
... These indices are used to enhance crop marks which are related to archaeological features. Indeed the results are very promising and indicate that vegetation indices can be applied in multispectral or hyperspectral dataset for the archaeological research [1][2][3][4][5]. ...
Conference Paper
This paper aims to introduce the spectral characteristics of a new Archaeological Index for supporting remote sensing applications in archaeological research. This index will be able to enhance crop marks, observed in satellite images, which are related to buried archaeological remains. For the aims of the research, ground spectral signatures were acquired from two agricultural areas of Cyprus (Alampra and Acheleia), specifically constructed in order to simulate buried archaeological remains. A complete phenological cycle of barley and wheat crops was recorded using the GER 1500 spectroradiometer with spectral range from 350 – 1050 nm (visible – near infrared spectrum). Correlation regression analysis and evaluation separability indices have shown that results are similar for both sites –regardless crop type. The spectral sensitivity, for enhancement crop marks, was detected at the red edge and near infrared spectrum (≈ 700 and ≈ 800 nm).
... Further to the above, special attention was given to the detection of crop marks. Crop marks, related to buried archaeological remains, have been recognized from aerial and satellite images (Parcak 2009;Masini 2005, 2007;Rowlands and Sarris 2007;Traviglia 2005). For instance, Alexakis et al. (2009Alexakis et al. ( , 2011 have used a combination of highand medium-resolution satellite data for the detection of Neolithic tells in the Thessalian plain, in central Greece. ...
Article
Remote sensing has been successfully used for the exposure of shallow buried relics such as archaeological remains. The detection is mainly based on photointerpretation of high-resolution satellite or aerial images. Photointerpretation for archaeological purposes is focused on the identification of crop marks using visible and near infrared VNIR spectrum e.g. vegetation indices response, which is sensitive to vegetation stress. Detection of such marks is always performed through images of adequate spatial resolution, and therefore this procedure might be problematic in cases when there is a lack of accessibility to such kinds of data. This paper addresses this problem and illustrates an image-based method intended for the detection of crop marks using satellite data of inadequate spatial resolution. The overall methodology consists of seven separate steps. The method needs two areas of interest to be selected in the image, preferably in close proximity to one another. The first area is characterized as the ‘archaeological area under investigation'while the second is a vegetated non-archaeological area. These two areas are simultaneously examined in detail using spectral signatures, soil lines, and their phenological cycle characteristics. The proposed methodology has been successfully applied in three different areas in Cyprus and Greece, where the authors have already used the technique for validation purposes.
... Indeed, various studies have shown that aerial and satellite imagery can be well suited for archaeological prospection (e.g. Αltaweel, 2005;Masini and Lasaponara, 2007;Cavalli et al., 2007;Parcak, 2009;Traviglia, 2005;Alexakis et al., 2009Alexakis et al., , 2011. Different applications of satellite remote sensing, field studies and Geographical Information Systems (GIS) were employed on archaeological sites in India by Pappu et al. (2010). ...
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An integration of geophysical surveys, ground hyperspectral data, aerial photographs and high resolution satellite imagery for supporting archaeological investigations at the multi-component Vésztő-Mágor Tell, located in the southeastern Great Hungarian Plain, is presented in this study. This is one of the first times that all these techniques have been combined and evaluated for retrieving archaeological information. Geophysical explorations, specifically magnetic gradiometry and ground penetrating radar methods, have revealed shallow linear anomalies and curvilinear rings at the Tell. The use of remote sensing images has confirmed the diverse anomalies with respect to geophysics through photointerpretation, radiometric and spatial enhancements. Moreover, several indices from ground hyperspectral data also have revealed stress vegetation anomalies. These integrated results were used to map the main areas of archaeological interest at the Vésztő-Mágor Tell and plan future excavations. It was found that these multiscalar data can be used efficiently for detecting buried archaeological features.
... The majority of these studies focused on the use of high resolution satellite imagery like IKONOS and QuickBird (Altaweel, 2005;Lasaponara and Masini, 2005. Hyperspectral satellite images such as HYPERION and MIVIS have been found to be suitable for retrieving valuable information in an archaeological context revealing buried architectural remains (Traviglia, 2005;Aqdus et al., 2007Aqdus et al., , 2008Bassani et al., 2009). ...
... The potential of these sensors for archaeological prospecting is self-evident. However, archaeological applications have so far mainly focussed on multi and hyperspectral imagery provided by airborne sensors such as MIVIS, CASI, ATM and AHS, which have a higher spectral, but lower spatial resolution (Traviglia 2005; Rowlands, Sarris 2007; Winterbottom, Dawson 2005; Rejas et al. 2006). Finally, ALS (Airborne Laser Scanning) or LiDAR (Light induced Detection And Ranging) (Lemmens 2007) has recently proven to be an actual breakthrough for archaeological research. ...
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This paper is intended to give an overview on current surveying techniques that use remotely sensed data, and their applications in archaeology. The focus is on optical 3D measurement techniques based on image and range sensors. Data and methods are briefly reviewed, whereas data processing and related problems are only touched on in passing. For the purpose of this review we distinguish three scales of archaeological research at which the surveying techniques discussed here can be applied: (1) the regional scale, to record the topography of archaeological landscapes and to detect and map archaeological features, (2) the local scale, to record smaller sites and their architecture and excavated features, and (3) the object scale, to record artefacts and excavated finds.
Conference Paper
Full-text available
A large number of technologies, such as Geographic Information Systems (GIS), Global Positioning Systems (GPS), Remote Sensing (RS), geophysical instruments, allows nowadays for fast and reliable automated capture, management and analysis of archaeological data. Beyond the City Walls (BCW) is a landscape archaeology project based in the countryside of the Roman municipium of Aquileia (Italy) that applies and integrates these technologies for the reconstruction of peripheral settlement dynamics in antiquity, trialling concurrently tools that operate as hubs for acquisition of disparate field data.
Article
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Riassunto L'impiego del telerilevamento per la definizione di strutture archeologiche costituisce una pratica ben consolidata che oramai presenta oltre un secolo di applicazione. Diversa è invece l'impiego di tale metodologia di rilievo per l'individuazione di strutture ancora sepolte. Allo scopo di validare questo approccio, pervenire ad obiettivi concreti e fornire indicazioni utili per gli addetti ai lavori, è stato effettuato uno studio nell'area del sito archeologico di Aquileia (UD). Il potenziale applicativo del telerilevamento in questo campo risiede nella possibilità data dall'integrazione con nuove tecnologie, in primo luogo dall'introduzione del laser a scansione, e dalla possibilità di giungere ad un impiego di tecnologie integrate. Il tutto associato ad una maggiore accuratezza nella geo-codifica dei dataset provenienti dai diversi sensori. Le meta-informazioni provenienti dai sensori iperspettrali agevolano le procedure di segmentazione dei dati laser, consentendo l'identificazione di numerose significative discontinuità dei DTM derivabili dagli stessi. Dall'integrazione dei due metodi sull'area di Aquileia è stato possibile ricostruire la posizione di importati manufatti sepolti quali mura ed elementi associabili a sistemi viari. È stato possibile ricostruire la posizione di un paleo-alveo probabilmente attivo in età romana mediante impiego del dato iperspettrale. I risultati ottenuti sono di notevole interesse avendo evidenziato elementi sino ad ora sconosciuti da sottoporre ad ulteriori studi ed indagini archeologiche. Abstract This paper deals with the integration of laser and hyperspectral data to improve the discovery of new archeological sites. We investigate the possibility of integrating such dataset in order to evaluate irregular behavior of some major ground indexes. While hyperspectral data allow the identification of specific humidity, vegetation and thermal conditions in the target area, accurate geometric information are provided by laser data. Optech laser and MIVIS and AISA hyperspectral data were acquired over the city of Aquileia (UD, North-East of Italy), an area of great historical interest due to many roman ruins. Significant results where obtained both in already discovered archaeological sites, and in interesting new areas on the northern side of the old city. When integrated, the resulting datasets showed, with sensible accuracy, the probable presence of surface/below surface archaeological elements.
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There is currently a great deal of interest in the quantitative characterization of temporal and spatial vegetation patterns with remotely sensed data for the study of earth system science and global change. Spectral models and indices are being developed to improve vegetation sensitivity by accounting for atmosphere and soil effects. The soil-adjusted vegetation index (SAVI) was developed to minimize soil influences on canopy spectra by incorporating a soil adjustment factor L into the denominator of the normalized difference vegetation index (NDVI) equation. For optimal adjustment of the soil effect, however, the L factor should vary inversely with the amount of vegetation present. A modified SAVI (MSAVI) that replaces the constant L in the SAVI equation with a variable L function is presented in this article. The L function may be derived by induction or by using the product of the NDVI and weighted difference vegetation index (WDVI). Results based on ground and aircraft-measured cotton canopies are presented. The MSAVI is shown to increase the dynamic range of the vegetation signal while further minimizing the soil background influences, resulting in greater vegetation sensitivity as defined by a “vegetation signal” to “soil noise” ratio.
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The relationships between various linear combinations of red and photographic infrared radiances and vegetation parameters are investigated. In situ spectrometers are used to measure the relationships between linear combinations of red and IR radiances, their ratios and square roots, and biomass, leaf water content and chlorophyll content of a grass canopy in June, September and October. Regression analysis shows red-IR combinations to be more significant than green-red combinations. The IR/red ratio, the square root of the IR/red ratio, the vegetation index (IR-red difference divided by their sum) and the transformed vegetation index (the square root of the vegetation index + 0.5) are found to be sensitive to the amount of photosynthetically active vegetation. The accumulation of dead vegetation over the year is found to have a linearizing effect on the various vegetation measures.
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In this study, Quickbird normalized difference vegetation index (NDVI) data were used in order to assess their capability in the field of archaeological prospection. The investigations were performed for a test case (Jure Vetere in the south of Italy) that is characterized by the presence of dense vegetation mainly composed by herbaceous plants. The results showed the high capability of QuickBird NDVI to enhance the typical surface anomalies linked to the presence of archaeological buried remains. The detected anomalies were confirmed by independent investigations based on geophysical prospections performed in 2005
Università degli studi di Trieste
  • La Carta Archeologica Del Friuli-Venezia Giulia
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Dati d'archivio e prospezione di superficie: nuove prospettive di ricerca per il territorio suburbano di Aquileia
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Maggi, P., Oriolo, F.: Dati d'archivio e prospezione di superficie: nuove prospettive di ricerca per il territorio suburbano di Aquileia. AAAd 45, 99-123 (1999)
Approdi nella laguna di Grado
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Gaddi, D.: Approdi nella laguna di Grado. AAAd 46, 261-275 (2001)