Spatial Science

Published by Taylor & Francis
Online ISSN: 1449-8596
Publications
Urban land cover classification, Istanbul and Hyderabad
Article
Urban morphology is characterized by a complex and variable coexistence of diverse, spatially and spectrally heterogeneous objects. Built-up areas are among the most rapidly changing and expanding elements of the landscape. Thus, remote sensing becomes an essential field for up-to-date and area-wide data acquisition, especially in explosively sprawling cities of developing countries. The urban heterogeneity requires high spatial resolution image data for an accurate geometric differentiation of the small-scale physical features. This study proposes an object-based, multi-level, hierarchical classification framework combining shape, spectral, hierarchical and contextual information for the extraction of urban features. The particular focus is on high class accuracies and stable transferability by fast and easy adjustments on varying urban structures or sensor characteristics. The framework is based on a modular concept following a chronological workflow from a bottom-up segmentation optimization to a hierarchical, fuzzy-based decision fusion top-down classification. The workflow has been developed on IKONOS data for the megacity Istanbul, Turkey. Transferability is tested based on Quickbird data from the various urban structures of the incipient megacity Hyderabad, India. The validation of both land-cover classifications shows an overall accuracy of more than 81 percent.
 
Article
Standard accuracy assessment in raster modelling assumes that desirable classes are exhaustively exclusive, location error either does not exist or does not affect classification, and classification results are crisp, not fuzzy. Failing to take these into account leads to propagation of the error. This paper introduces a fuzzy weighted Kappa measure as a global statistic which takes both of these sources of uncertainty into account in classification accuracy assessment. Calculation of the fuzzy weighted Kappa measure involves three processes. First, a virtual confusion matrix is constructed to incorporate the fuzziness of location. Then a similarity weight matrix is derived to represent the fuzziness of the category. Combining the virtual confusion matrix and the similarity weight matrix, the fuzzy weighted Kappa is calculated using the weighted Kappa algorithms. The fuzzy weighted Kappa is shown to be more flexible than standard methods and gives results closer to an intuitive assessment of accuracy. Although calculating the fuzzy weighted Kappa involves a degree of subjectivity, this poses no major limitations on the usefulness of the measure. It is therefore proposed as an alternative classification accuracy measure for the remote sensing and GISc community.
 
Article
This paper presents an application of a cellular automata model to map the spatio-temporal processes of urban development in Metropolitan Sydney, Australia over the period of 1971 to 1996. By comparing the model's output to the actual urban development of Sydney over the same time period, the accuracy of the model was evaluated and the model validated. The results identify dual roles for the cellular automata model of urban development as an analytical tool to explore and evaluate the impacts of the rules underpinning the processes of urban development of Sydney, and as a planning tool to examine the outcomes of various options for urban development.
 
Article
Reflectance and derivative spectra of greenhouse-grown mopane (Colophospermum mopane) were analyzed to investigate whether the interactive effect of soil phosphorus and nitrogen treatments on plant-chemical composition can be detected using non-destructive techniques. Reflectance spectra were affected by changes in soil nitrogen. Derivative spectra showed significant differences as a result of nitrogen and phosphorus treatment. Several spectral bands that showed different spectral signatures between soil treatments also showed significant correlation to condensed tannin, phosphorus and nitrogen concentration in mopane leaves. This shows the potential to detect the effect of soil properties on the plant's physiology with hyperspectral remote sensing
 
Article
Hyperspectral reflectance (350nm - 2500nm) measurements of growing peanut leaves were used to predict the kernel maturation stage as well as the incidence of aflatoxin within peanut pods. For the prediction of harvest date, explanations of variance of > 95 percent were obtained while explanations of variance of > 81 percent were achieved when differentiating plants with pods contaminated with aflatoxin from those with uncontaminated pods. An explanation of variance of 85 percent was also identified in the prediction of actual aflatoxin concentration within the pod via the spectral properties of a growing leaf. Multispectral satellite imagery also proved accurate in identifying maturity variations across a peanut crop as well as regions of high aflatoxin risk.
 
Article
Object-based remote sensing image classification is known for its ability to elicit objects that correspond one-on-one with real-world objects. However, it is still subject to a two-stage linear segmentation and classification process and a limited ability to use geometry, class identity and neighbourhood information in that process. This paper explores the scope of intelligent vector agents (VAs), potentially unifying segmentation and classification, and, as implemented through the Geographic Automata System framework, explicitly modelling a set of vector objects with (1) elastic geometry, (2) states, (3) neighbourhoods and embedded rules connecting all three. A brief illustration involving geometry, geometry rules and states is presented.
 
Article
Motivated by the need for hydrologically adaptive representations of urban environments for hydrological modelling, this paper proposes a Hexagonal Hierarchical Surface Model (HHSM) and an equivalent Rectangular Hierarchical Surface Model (RHSM). The HSMs are point-based Level of Detail (LoD) models that store values in array trees. Both HSMs use an intrinsically hierarchical indexing system across both the tree and array components of the data structure, which facilitates neighbourhood operations, adaptive surfaces and multi-level analysis. An investigation of variable resolution flow direction arrays using a mathematically defined cone surface shows that at the highest levels of detail, rotation between LoDs in the HHSM causes significant loss of accuracy if flow directions are restricted to the directions of a cell's neighbours. There is no such effect in the RHSM. These findings suggest unrestricted flow direction algorithms such as D∞ are required for adaptive hexagonal flow direction arrays.
 
A map of the area the experiment took place and the two routes. Circles correspond to intersections.  
; F(11, 11) = 3.80, p < 0.05). Map-learners overestimated the distance (Binomial Test: 2 underestimations vs. 10 overestimations, p = 0.039) which was not the case in direction-learners (Binomial Test: 5 underestimations vs. 7 overestimations, p = 0.774). 
A participant walking the route followed by an experimenter recording the dependant measures.  
Article
When planning a route we usually study a map, ask other people for verbal directions, or use a route planner. Which source of information is most helpful? This experiment investigated human wayfinding and knowledge acquisition in urban environments. Participants were required to retrace two different routes learned either from route maps, or from verbal directions. This research shows that both maps and verbal directions are equally useful tools for conveying wayfinding knowledge. Even the survey knowledge of map-learners was not better. The authors argue that both verbal directions and maps are memorized in a language-based format, which is mainly used for wayfinding.
 
Article
Ground shaking associated with the 22 February 2011 Mw 6.2 Christchurch earthquake exceeded MM10 and dislodged boulders from cliffs on the upper slopes of the Port Hills, southeast of Christchurch City. Boulders rolled into the urban areas below. Cliffs on the lower slopes collapsed and debris avalanches inundated homes built at their bases and undercut homes built at their crests. Boulders and debris avalanches impacted over 200 buildings and killed five people, resulting in widespread evacuations. Large aftershocks caused further boulder rolls and cliff collapses. Before buildings could be reoccupied a life-safety risk assessment was required. This study included pilot investigations of the 19 worst affected areas and these were used to develop hazard and risk models. Once ground verified, the models were extended to the entire Port Hills area. GIS was the main tool used in the development of the models, but other tools and techniques were also utilised.
 
Article
Ellipsoidal heights, i.e., w.r.t. a geometrical Earth figure, determined from Global Navigation Satellite Systems (GNSS) are inherently their least accurate coordinate, due mainly to satellite geometry and atmospheric refraction. For most practical purposes, however, these GNSS-derived ellipsoidal heights have to be transformed to heights that relate to the Earth’s gravity field, which generally adds further uncertainty. The reduction in accuracy of the transformed height is due to errors in gravimetric quasi/geoid models, but this is compounded yet further in Australia and elsewhere because of the imperfect realisation of local vertical datums. This paper comments upon current, emerging and future issues with height determination on the Australian Height Datum (AHD) using GNSS. This comprises the reference frame used for GNSS ellipsoidal heights, theory- and data-driven inaccuracies in modelling the quasi/geoid, and deficiencies in the realisation of the AHD. While some of these issues will be redressed, in part, by the production of AUSGeoid2008 that is fitted to the AHD, there will always be the need to routinely apply checks on GNSS-derived heights in Australia, and elsewhere.
 
Article
The demand for geospatial information has risen greatly while supply is still catching up. Particularly in Australia, the availability of seamless national datasets is largely supply driven. An improved understanding of user needs is required in order for future initiatives to better account for the demand side of the location information market. This paper looks at the system of national location information in Australia, within the context of PSMA, a provider of authoritative national geospatial datasets. This is undertaken as the initial stage of a user needs assessment. Results provide a new conceptual understanding of the system with its external influences, constraints and opportunities. In particular, users are classified as a key stakeholder within the system. External influences of note are the activities of the Office of Spatial Policy, the Australian Government's whole-of-government initiatives and the need to move towards demand-driven or solutions-based spatial data themes.
 
Landsat 5 Thematic Mapper subset acquired on the 8th August 2004 of Moreton Bay, South East Queensland, Australia with the field study sites used for calibration and validation for seagrass cover maps.
Areas of Moreton Bay included in the seagrass map and the data sources used to derive the maps.
Article
Creating accurate maps of seagrass cover is a challenging procedure in coastal waters with variable water clarity and depths. This paper presents an approach for mapping seagrass cover from data sources commonly collected by natural resource management agencies responsible for coastal environments. The aim of the study was to develop an approach for mapping classes of seagrass cover from field and/or image data for an area with variable water clarity and depths. The study was carried out in Moreton Bay in eastern Australia. A Landsat 5 Thematic Mapper satellite image was acquired for the same area in August 2004. The image data were used to map seagrass cover in the exposed inter-tidal and clear shallow water areas to depths of 3 m. Field survey data were collected, in July - August 2004, to map deep (> 3 m) and turbid sub-tidal areas, using: real time video, snorkeller observations and transect surveys . The resulting maps were combined into a single layer of polygons, with the same seagrass cover classes used as existing mapping programs and with each polygon assigned to one of five cover classes (0 %, 1-25 %, 25-50 %, 50-75 %, 75-100 %). As independent field data were not available for accuracy assessment, a reliability assessment indicated that > 75 percent of the Bay was mapped with high categorical reliability. Most previously published seagrass mapping projects covered areas < 400 km2, were based on single data sets, and lacked assessment of accuracy or reliability. Our approach and methods address this gap and present guidelines for a generally applicable method to integrate image and field data sets over large areas (> 1000 km2) commonly used for monitoring and management.
 
Article
Using four types of fire incidence, namely calls for property, vehicle, secondary fires and malicious false alarms, this paper explores their spatiotemporal dynamics and the relationship to socioeconomic status. Combining both spatial and temporal dimensions using a novel technique, called the 'comap', each incident type is visually explored, arguing that its application permits new insights into their dynamics and allows questions Such as - for a particular type of fire incident what are the salient spatio-ternporal patterns and how do these vary for differing levels of disadvantage, to be answered for the first time.
 
Article
In 1829 the Swan River Colony was established by Captain Stirling and England claimed the remaining western portion (New Holland) of the Australia continent up to the NSW border at 129° longitude. Eventually NSW was further reduced in area to create the State of South Australia (SA) and the Northern Territory (NT) that now share the common border with WA. It was not until 1921 that the two states of WA and SA agreed on a process to determine the accepted legal position of the Border. This agreement included the placing of two Cairns, the Kimberly Cairn and the Deacon Cairn, on the border at 129° longitude as determined from adjacent astronomical observations. These two cairns under the agreement now determine the physical location of the border today. In 2012, GPS surveys were carried out at both cairns to determine the accuracy of the two original surveys.
 
Article
Review of "Opinion of the Solicitor-General regarding the Claim of the Government of Victoria to the Territory (known as the Riverina) lying between the Murray and Murrumbidgee Rivers, together with Maps showing the course of the River Murray", William Applegate Gullick, Government Printer, Sydney, 1912, 18 pp and including an Appendix of 17 fold-out maps of south-eastern Australia showing the history of discovery of the course of the River Murray, 7s. 6d. at the time of publication (1912), and several hundred dollars at the time of acquisition (2004) by the Education Resource Centre Library of the University of Melbourne.
 
Article
This paper reviews a field that is herein termed spatial ?non-stationarity?, which is specifically concerned with non-stationarity in the geodetic theory of least-squares collocation (LSC). In practice, many geodesists rely on stationary assumptions in LSC, i.e., using a constant mean and isotropic and spatially invariant covariance for estimation and prediction of geodetic quantities. However, new theories in spatial statistics and geostatistics allow for better statistical methodologies to be used in geodesy. The aim of this paper is to introduce these methodologies and adapt them for dealing with non-stationarity in LSC.
 
Article
This work provides insight into the Croatian Local Spatial Data Infrastructure (LSDI). Field data collected in 2012 by means of a questionnaire formed the basis of this work. The questionnaire respondents were Croatian cities. The results were analysed according to city population, city budget and city area. An analysis was also performed according to European Union Nomenclature of Territorial Units for Statistics 2 regions. Analysis showed significant LSDI differences between bigger and smaller cities. Some of the LSDI indicators are more suitable for Croatian relations than other. The indicators used and the analysis of their reliability could be adopted in other countries.
 
Article
A large number of models and mapping functions have been developed for use in the analysis of space geodetic data. The performance of tropospheric delay prediction models used for GPS degrades at very low elevation angles. On the other hand, most standard tropospheric models were experimentally derived using available radiosonde data, which were mostly observed on the European and North American continents. In this paper an investigation is presented of several models, including those developed by Hopfield, Saastamoinen, Niell (NMF), Chao, Black & Eisner (B&E), Yan & Ping, Vienna (VMF) and Isobaric (IMF), to determine the errors of these models in predicting dry tropospheric delay and to present a new mapping function which has better low elevation angle performance up to 5° and is suitable for the atmospheric conditions of Egypt. A very significant improvement in the GPS height component can be achieved by using the new mapping function especially for the atmospheric conditions of Egypt.
 
Article
This paper describes the development of an e-research facility for socio-spatial analysis. It is illustrated with the example of a prototype Web-based GIS and statistical application for the analysis, modelling and visualisation of the relationships between patterns of voting at the 2007 Australian federal election and the demographic and socio-economic characteristics of local populations using 2006 census data. The facility incorporates a web-based GIS which can generate maps displaying patterns of voting for political parties across polling booths with overlay data showing the population characteristics living within the surrounding polling booth catchments. Various classification approaches including equal interval, quantile, median-based natural breaks, and location quotients can be used to generate different map displays. Statistical analysis functionality - such as regression analysis, cluster analysis and discriminant analysis - enables researchers to conduct on-line statistical modelling and the visualisation of outputs. This prototype facility not only gives researchers and students on-line access to socio-spatial datasets through a metadata directory, but also enhances the capacity and capability of researchers and students to undertake spatially integrated social science research.
 
Article
Each of the existing models for direction relations has its advantages and disadvantages, but none of them can meet the five criteria used to evaluate a satisfactory model, i.e. correctness, completeness, efficiency, quantification and qualification. Hence, this paper proposes a new model that integrates the advantages of existing ones using two strategies. First, the method for partitioning direction regions is improved so that the new model is correct, complete and efficient; second, the idea for calculating and describing direction relations in the direction-relation matrix model and the Voronoi-based model is integrated into the new model so that direction relations can be represented both qualitatively and quantitatively. Our experiments show that the model can calculate direction relations between arbitrary object pairs in two-dimensional spaces and the results are acceptable to a majority of people.
 
Article
This paper describes the development of a prototype Web geographical information system for mapping aspects of quality of life derived from a survey of residents in the Brisbane-South East Queensland conducted in 2003. Using cluster analysis, "downshifters" - people who voluntarily make a long-term change in their lifestyle following the decision to "downshift", other than planned retirement, which reduces their income - are categorised. Principal component analysis was used to examine the performance of statistical local areas against three perceived components of neighbourhood attractiveness aesthetic, amenity and social interaction - that underlie the residential location decision choice of survey respondents. Spatial distributions of downshifters and neighbourhood attractiveness can be visualised with a Web browser.
 
Article
This special feature in the journal of Spatial Science brings together a collection of papers showing environmental monitoring and management applications of high spatial resolution remotely sensed image data. As illustrated by the papers in this special feature, and a growing number of papers in ecology, environmental management and remote sensing journals (Butler, 2006; Mumby et aL, 2001; Zanoni and Goward, 2003), there is an increasing need for spatial information derived from multi-spectral sensors at the scales of traditional aerial photography. The application of moderate spatial resolution image data has produced limited results for mapping and monitoring small features (< 10 m) within terrestrial and aquatic habitats, Such as individual tree crowns and their associated biophysical variables, coral reef structures and seagrass distribution. With nominal spatial resolutions less than 5 m x 5 m, there now exists the capacity to acquire fully radiometrically and geometrically corrected data to map and monitor complex structures and patterns of small features. High spatial resolution airborne and satellite digital image sources in various forms are now easily obtainable for agencies responsible for monitoring natural and built environments. Spatial data, including airborne and satellite images, are globally accessible thanks to Virtual Globes, such as GoogleEarth and Microsoft's Virtual Earth. Organisations responsible for managing natural and built environments are now faced with choices of how to transform these data into management-relevant spatial information. Many standard per-pixel based approaches developed for moderate spatial resolution image data do not work on single- or multidate high spatial resolution image data, and it is not efficient to subject these data to visual interpretation. The papers presented in this special issue illustrate a variety of approaches developed to address some of these challenges in terrestrial and aquatic environments.
 
Article
This preface gives an overview of the seven papers featured in the SIRC NZ 2013 Special Feature of the Journal of Spatial Science, to be published in September 2014.
 
Article
Flickr and Panoramio are fast-growing photo-sharing services that contain millions of geotagged images contributed by Web users from all over the world. This study analyses the positional accuracy of 1433 images for 45 areas in four selected world regions by comparing the geotagged position of photos to the manually corrected camera position based on the image content. The analysis reveals a better positional accuracy for Panoramio than for Flickr images, and some effects of image category and world region on positional accuracy. These findings can be helpful when considering Flickr and Panoramio images as data sources for future geo-applications and services.
 
Article
Discriminating increaser species is important for mapping rangeland degradation. The main objectives of this paper were to (1) determine whether four increaser species could be discriminated from each other and (2) determine the key wavelengths that have high discriminatory power. Spectral data were taken at canopy level from Hyparrhenia hirta, Eragrostis curvula, Sporobolus africanus and Aristida diffuse from Okhombe rangeland, KwaZulu-Natal province, South Africa. A field portable analytical spectral device with spectral range from 350 nm to 2500 nm was used in the analysis. Three-tier hierarchical techniques of One-way ANOVA, stepwise discriminant function analysis and canonical function analysis were used. The results revealed that there were statistically significant differences in spectral reflectance among four species on 439 wavelengths. The most important eight wavelengths (665 nm, 729 nm, 848 nm, 895 nm, 1039 nm, 998 nm, 681 nm and 972 nm) that have been selected for spectral discrimination were largely located in the visible, red-edge and near-infrared regions of the spectrum. The three tiers of analysis yielded species discrimination with an overall accuracy of 83 percent and a KHAT value of 0.77. The use of the spectroscopic approach applied in this study indicated that the increaser species were spectrally different. Therefore, these results encouraged further investigation into the possibility of mapping increaser species as indicators of different levels of rangeland degradation.
 
Article
To address blur and noise issues caused by airlight and atmospheric scattering in nighttime imaging environment, we proposed a multi-frame image restoration method. First, the Luojia 1–01 night-light image degradation model was derived. Thereafter, the APSF (Atmospheric Point Spread Function) for night-light images was estimated. Improved dark channel prior and sparse constraint models were used to eliminate effects ofairlight and atmospheric scattering. Finally, a multi-frame sparse constraint model was established to eliminate image noise. The results show the proposed method is effective as it can reduce the image blur phenomenon, suppress image noise, and improve image quality.
 
Article
February 1, 2017, EOP 14C04 aligned to the ITRF2014 was adopted by IERS. To assess the improvement of EOP 14C04, the differences between EOP 14C04 and EOP 08C04 are firstly analyzed. Then, the causes of the differences between the two solutions are examined. Finally, the differences are further assessed for their prediction performance using the LS+AR model. The results demonstrate that (1) there is a trend in the difference between the two solutions; (2) the cause of the above-mentioned difference should be attributed to the different reference frames; (3) the new EOP 14C04 shows better performance for high-frequency signals.
 
Article
For the error analysis of the GPS velocity component we have to consider many factors, including the determination of the stochastic model. In this article we intended to analyse the results obtained by using data gathered during a period of 18 months. The presence of the noise contained within the GPS station coordinate time series is recommended to be fitted by using a linear trend to the coordinate’s time series and after this procedure to model the noise properties of the residuals. For the noise determination we used a first-order Gauss-Markov model – FOGM. To see the behaviour of the chosen noise model, we used the power spectra density of the residuals and the log likelihood values and we compared the results with those from the power law plus white noise model. In the estimation process we used the semiannual sinusoidal signal to express the seasonal influence. The amplitudes and phase lag of the seasonal variation were also computed. Although the noise that has a large contribution in a relatively short data span – shorter than 2.5 years – is considered to be white noise, using the average we have shown that the presence of coloured noise has to be taken into account.
 
Article
Spatial depiction of wheat and predicting yields are crucial for national food security measures. This study has employed multi-temporal synthetic aperture radar (SAR) data for spatial mapping of winter wheat and estimating its acreage in the Gorakhpur district. Results showed that the estimated acreage of winter wheat based on SAR data was 189,740 hectares. Accordingly, the yield and production were predicted as 3.9 tonnes/ha and 740,000 tonnes, respectively, using a polynomial model. VH polarisation was effective in acreage mapping compared to VV. Thereby, the developed framework could support policymakers by giving advanced estimates of area and yield.
 
Article
This paper charts the development of the unique nature of the New Zealand Surveyor from navigator and early explorer to the multi‐discipline land development consultant of the 21st Century. The structural changes that have taken place in government institutions are identified with an explanation of why these changes were necessary. The consequential effects on the survey profession are also outlined, together with an assessment of how the principal surveying professional body has responded.
 
Article
The massif of Saghro in Moroccan Anti-Atlas is known for several important economic deposits. Thanks to its high potential in terms of production, the deposit of Bouskour is considered among the most important and promising ones on the national scale. The objective of this work is to evaluate the potential of the new Multispectral Landsat-8 OLI and Sentinel-2A sensors in comparison with the Terra ASTER sensor in mineralogical mapping. This task was completed using the band ratio (BR), independent component analysis (ICA) and mixture tuned matched filtering (MTMF) methods. In addition, a field survey was carried out in order to control and validate the obtained mineralogical abundances. The approach followed gave satisfactory results with respect to the field data and the previous studies. Therefore, the sensors used showed great potential for mineralogical mapping and they can be exploited in other regions.
 
Article
This paper introduces Singapore Views as a novel 3D-4D interface to visualize large space-time datasets with applications in smart cities. The engine enables a combination of geographic information system, geo-located data with high-resolution 3D models and multimedia. Space-time datasets from Singapore’s National Science Experiment (NSE) 2016 are used to test the functionality of Singapore Views. The findings from the user study revealed the new visualization engine was helpful in extracting insights from space-time data. Finally, this study also contributes to the current discussion of how to visualize knowledge thereby support the planning of smart cities.
 
Article
Coordinate transformation is indispensable to unify the three-dimensional (3D) points between different coordinate systems. Traditional methods are generally two-step work: transformation parameter estimation and coordinate transformation. Unlike traditional methods, this paper proposes a direct 3D coordinate transformation method based on the affine invariance of barycentric coordinates. The proposed method avoids solving transformation parameters and requires neither the initial values nor the iterations. Experiments based on LiDAR point cloud registration and coordinate transformation demonstrate that the proposed method can reach or even outperform traditional methods, and is suitable for both similarity and affine transformation of 3D points with strong anisotropic scaling.
 
Article
Positioning integrity is essential in navigation. A novel approach is proposed for integrity monitoring that combines the Advanced Receiver Autonomous Integrity Monitoring (ARAIM) with Non-Line-of-Sight (NLOS) detection method using 3D city models to aid multi-constellation GNSS positioning in challenging urban scenarios. A demonstration of the proposed approach is performed with real data in an urban area in Hong Kong. The combined technique is tested via Single Point Positioning and simulated DGNSS positioning using a commercial-grade receiver. An improvement of fault detection capability and accordingly the obtained accuracy is shown when combining the two methods, compared to applying each method individually.
 
Article
We present the GLIMPSE system that provides a framework for storage, management, accessibility and integration of 3D LiDAR data acquired from multiple platforms. We detail a point cloud retrieval approach, which provides spatially optimised access to point cloud data from the system for a particular geographic area based on user specifications. We tested our point cloud retrieval approach to facilitate the extraction of road medians from large volumes of ALS data stored in the GLIMPSE system. The integrated use of a geospatial database, the GLIMPSE system and the point cloud retrieval approach improved the efficiency of road median extraction.
 
Article
With the increasing size and complexity of modern buildings, 3D indoor routing is receiving more attention nowadays. Different elements such as route finding, indoor modelling, and route visualisation need to work together to achieve this goal. For this purpose, we propose a framework that makes use of existing data sources and tools that can minimise the time and effort needed for potential 3D indoor routing applications. Our 3D indoor and building models are generated from CAD files and building footprints using CityEngine and its built-in procedural modelling approach. An Americans with Disabilities Act (ADA) compatible 3D network is created by combining 3D floor lines and transitions such as staircases and elevators. The resulting routes as well as the indoor and façade models are then visualised through a 3D WebScene generated by CityEngine. Our study demonstrates the usefulness of CityEngine for 3D indoor model generation as well as 3D routing visualisation.
 
Article
The low accessibility of information regarding the design and construction phases and the current state of the buildings is the main cause of inefficient actions on existing buildings. The lack of ‘as built’ documentation and the complex task of detecting their current status in terms of use and maintenance cause deep difficulties in planning appropriate interventions. This paper shows the findings of a research aimed at testing the integrated use of BIM and 3D GIS in order to structure knowledge. The work led to the development of a BIM-3D GIS workflow that was tested on two case studies in Italy. .
 
Article
Recently, it has been shown how quaternion-based representation of a rotation matrix has advantages over conventional Eulerian representation in 3D similarity transformations. The iterative estimation procedure in similarity transformations based on quaternions results in translations and (scaled) quaternion elements. One needs, therefore, an additional procedure for evaluating the rest of the transformation parameters (translation, scale factor and rotation angles) after this solution.This contribution shows how to evaluate the rotation angles and the full covariance matrix of the transformation parameters from the estimation results in asymmetric and symmetric 3D similarity transformations based on quaternions.
 
Article
This paper presents a knowledge reuse framework to solve the problem that modelling knowledge cannot be reused effectively in the process of generating multi-type railway scenes. We designed the contents and instantiation method of the modelling knowledge templates. Then, we discussed in detail how to parse the modelling knowledge templates Finally, we designed the scene mapping and instantiation method. We developed a prototype and carried out experiments. The experimental results show that our method is applicable to unified modelling of different types of 3D railway scenes on the same platform, enabling reuse of primitive models, 3D scenes and modelling knowledge.
 
Article
Flood damage assessment (FDA) provides an effective basis for the flood risk management process to evaluate and treat risks. Current FDA methods, however, are ill-equipped to account for the distinctiveness of buildings in the analysis. This is mainly due to their limited input data that on the one hand requires complete building information (well-represented in building information models [BIM]) and, on the other hand, the flood information (commonly managed by geographic information systems [GIS]). While such requirements cannot be satisfied via independent use of BIM or GIS, their integration can potentially be used for this purpose. The current BIM-GIS integration methods, however, are limited or application-specific. Therefore they fall short in satisfying the micro-level FDA information requirements. This paper presents a new data model as a profile of Geography Markup Language (GML) for BIM-GIS integration to support the detailed assessment and 3D visualisation of flood damage to buildings. The model was further evaluated using a case study and found effective for this purpose.
 
Article
Through an unmanned vehicle payload calibration campaign experiments, both reflectance-based and irradiance-based methods are used to calibrate multispectral sensor. The results show that both methods achieved good linear relationships between the digital numbers and apparent radiances (R² > 0.99). Validation results demonstrated the relative error between the radiometric calibration and radiative transfer calculation ranged from 0.91% to 21.05%. The error analysis suggested that the irradiance-based method is less sensitive to aerosol parameters. However, the relative differences between these two methods are small under low aerosol loading conditions, suggesting the irradiance-based method may be a good option with some improvements.
 
Top-cited authors
Will Featherstone
  • Curtin University
Ian Phillip Williamson
  • University of Melbourne
Stuart Phinn
  • The University of Queensland
Abbas Rajabifard
  • University of Melbourne
Joaquin Wallace
  • Golden Gate University