Three-dimensional Geographic Information System Research Articles

Spatio-temporal GIS Design for Exploring Interactions of Human Activities

An effective representation of human activities in geographic information systems (GIS) presents a challenging research topic. Recent developments of information and communication technologies (ICT), which enable a virtual space and allow people to interact with others remotely, make such efforts even more difficult. This paper first extends the space–time path concept of Hägerstrand's time geography to represent both physical and virtual activities in a space–time context. A spatio-temporal GIS design which can accommodate the extended space–time path concept is proposed to support the exploration of spatio-temporal patterns of human interactions in physical and virtual spaces. Using time as a linear referencing system, a temporal dynamic segmentation method was developed to dynamically locate physical and virtual activities on space–time paths. The GIS design supports the identification of four different spatio-temporal patterns (i.e., co-existence, co-location in space, co-location in time, and no co-location in either space or time) of human interactions through their space–time paths. Using a hypothetical activity dataset, a prototype system is implemented as a three-dimensional GIS (i.e., two-dimensional space + one-dimensional time) in ArcGIS. The prototype system demonstrates the feasibility and potential of applying spatio-temporal GIS concepts to extend Hagerstrand's time–geographic framework for the representation and analysis of human interactions in both physical and virtual spaces. The proposed GIS design can be useful in such applications as understanding traffic congestion, tracking terrorist activities, and modeling the spread of infectious diseases.

Mobile Digital Cameras for As-Built Surveys of Roadside Features

A method for determining the three-dimensional locations of roadside features appearing on multiple sequential images captured using a mobile video-logging system without any ground control is described. The digital camera was calibrated using a special three-dimensional calibration range and Calib software to simultaneously determine the interior and exterior orientation elements on a local system. The software was then used to determine the local three-dimensional coordinates of roadside features using the sequential imagery from the mobile video-logging system captured along a highway at highway speed. The relative locations were transformed to the absolute locations using the locations of the camera’s exposure stations from the Global Positioning System. The relative accuracy of the locations obtained was 5 cm, and absolute accuracy using the code phase kinematic Global Positioning System was 2 m. This paper also shows the two-dimensional geographic information system, three-dimensional geographic information system, and virtual reality created for three test sites using the imagery from the mobile video-logging system.

An object-oriented data model for complex objects in three-dimensional geographical information systems

Developing a three-dimensional (3D) data model for Geographic Information Systems (GIS) is an essential and complex issue. 3D modelling in GIS is becoming ever more important for the development of cyber cities and digital earth, which have recently become feasible. A competent 3D model forms an efficient foundation for 3D visualization, query and spatial analysis. As a development of the existing 3D models, this study proposes particular improvements in handling complex 3D objects. We present an object-oriented data model for handling complex 3D objects in GIS. First, the conceptual data model is developed based on the principle of object-oriented (OO) data modelling. This model is designed based on the following three basic geometric elements: node, segment and triangle. Accordingly, the abstract geometric objects are defined: including points, lines, surfaces and volumes. Second, the corresponding 3D logical model is designed based on the defined abstract objects and the relationships between them. Third, a formal representation of the 3D spatial objects is described in detail. Fourth, a prototype 3D GIS is developed based on the proposed 3D data model. Finally, we describe the results of an experimental study to reconstruct 3D objects using this 3D GIS and a comparison with the performance of other 3D data models. The proposed model is able to handle complex objects, such as complex buildings and TV towers, which is an essential functionality for building large-scale cyber cities, such as for Hong Kong. The proposed data model proves to be very efficient, particularly in visualization and rendering. The experimental results show which the data volume of the proposed model is compacted and the visualization speed for 3D objects is improved, compared with the existing models.

Developing a Geographic Information System (GIS) for Mapping and Analysing Fossil Deposits at Swartkrans, Gauteng Province, South Africa

The accumulation of fossil remains, bone tools, and stone tools at the Plio-Pleistocene site of Swartkrans has been attributed to a variety of depositional agents. These agents include hominin activity, carnivore activity, alluvial deposition, and gravitation. Based on recent studies, it is highly probable that the accumulations found at Swartkrans and other Plio-Pleistocene cave sites in South Africa have resulted from a combination of these processes. In order to explore further the taphonomic nature of Swartkrans, a Geographic Information System (GIS) was developed combining all existing information produced from the final seven-year period of C. K. Brain's excavations and a recent survey of the site. The amalgamation of this information into a GIS has resulted in a digital archive of Swartkrans information that allows the user to simultaneously visualize and analyse fossil, artifact, and geological materials within their original spatial contexts allowing a more comprehensive investigation of the site post-excavation. Three-dimensional reconstruction and GIS development for sites such as Swartkrans present many obstacles when using traditional GIS approaches. Due to the presence of overhanging features, certain limitations of conventional GIS software yield erroneous results. These limitations are based on the fact that conventional GIS packages interpret Z values as attributes rather than as true spatial coordinates. A brief overview of GIS and the challenges involved in the mapping and three-dimensional reconstruction of sites such as Swartkrans using traditional GIS approaches are discussed, as well as potential applications of the system.

An Integrated 3D GIS Model of the Yellowknife Camp: A Tool for Efficient Development

As an integral part of the Geological Survey of Canada’s EXTECH III Project, a three-dimensional computer model has been created of the Con and Giant gold mines in the Yellowknife Greenstone Belt. The Yellowknife Mining Camp has produced a great deal of gold (over 15 million ounces, or 400 000 kg) in the past sixty years and the prevailing assumption is that the mines are at the end of their lives. However, the potential for discovering additional resources using new ideas and technology, and maximizing use of existing data, offers an opportunity to sustain the old mining operations and maintain their contribution to the community. The objectives of this study included the compilation and creation of a three-dimensional Geographic Information System model (combining 3D subsurface data with surface information) to provide a framework for concurrent structural and alteration studies, and to encourage new exploration in the area. A secondary objective was to retain the data in digital format as a historical reference for future remediation efforts, and to document a portion of Canada’s rich mining history. The end result is a database and set of models that have been instrumental in facilitating further exploration in the area, as well as in developing targets for future exploration and mining activities. In addition, the EXTECH III 3D GIS model has made a valuable contribution toward the understanding of the arsenic remediation issues at the Giant mine, and has served as a tool in support of a variety of highly technical engineering studies and for communicating information and problems to the layman and community as a whole.

Measuring Uncertainty of Spatial Features in a Three-Dimensional Geographical Information System Based upon Numerical Analysis

This paper defines an uncertainty description – a discrepancy that is a deviation of a measured value from its ‘true’ value – for three-dimensional (3D) vector data and proposes an uncertainty measure to quantify the uncertainty description. In an existing research issue, uncertain 3D spatial features was simulated and compared with the ‘true’ location of the spatial features in order to estimate an average value of a discrepancy of the spatial features. However, this time-consuming method cannot provide a precise and highly accurate solution. This study further proposes the development of a numerical uncertainty model for 3D spatial features. The expected value of the discrepancy is expressed as a multiple integral and solved by a numerical integration technique. Some preliminary test results from experimental data are summarized and compared with those from the earlier simulation model.

Tectonic model and three-dimensional fracture network analysis of Monte Alpi (southern Apennines)

The Monte Alpi (southern Italy) is well known as an outcropping analogue of the Val d'Agri subsurface units which host a number of oil fields of economic importance. This paper presents an example of a detailed study which integrates stratigraphy, structural geology, tectonic analysis and fracture network study. The new structural model presented is based on a detailed 1:12,500 field survey of the area, whose results are illustrated in a comprehensive outcrop map, geological map and structural cross-sections, and stereographic projections and palaeostress inversion calculations of a mesostructural data set. The Monte Alpi Unit is characterised by a 2000-m-thick sequence of Jurassic–Cretaceous platform carbonates, conformably covered by Middle–Upper Miocene calcarenites. This sequence is unconformably covered by Upper Messinian terrigenous clastics, mainly along a number of major growth faults. Our detailed mapping revealed that the Monte Alpi Unit is tectonically overlain by the Lagonegro basinal Unit (thin siliceous carbonates and remnants of pelagic pelitic and carbonate deposits, all highly deformed) and by the Monte la Spina Unit (cataclastic Mesozoic carbonates and dolomites). This solves earlier raised questions concerning the palaeogeographic provenance of the carbonates outcropping in the area, which can thus without any doubt be correlated with the external carbonate domains known from the subsurface. The present-day structure shows a structural inversion along the major Late Miocene growth faults which acted as sinistral transpressive faults. The latter faults are part of a regional set dissecting the southern Apennines, active up till at least Middle Pleistocene times. A fracture study was performed on the Mesozoic carbonates of the area in order to collect data regarding length distribution, orientation, density and spatial heterogeneity of the fracture network to be used for considerations regarding exploration and development of the Val d'Agri reservoirs. The data were collected on 37 horizontal (strata-parallel) and vertical outcrop surfaces through photographic restitution and digitising of fracture lineament traces, and measurements of orientations of all visible fractures. Furthermore, three major outcropping rock walls along the flanks of Monte Alpi and Santa Croce were photographed and fracture and fault zone lineaments were digitised. All data were inserted and calibrated in a three-dimensional (3D) Geographic Information Systems and Computer Aided Design (GISCAD) environment consisting of a database and a 3D geographical framework comprising topographic map, Digital Terrain Model (DTM), geological map, aerial photograph lineament map and a 3D reconstruction of major fault surfaces. Making use of the potential of the 3D working environment, outcrop surfaces and rock walls were reconstructed at their correct 3D position and orientation. Data analysis comprised stereographic contour diagrams and rosette diagrams of 1800 fracture orientations in order to recognise main fracture sets. Three corrections were performed on these data: length weighting, Terzaghi correction (removal of sample orientation bias) and tilt removal. From a comparison between orientation data on various scales combined with field evidence, it can be deduced that fault and fracture sets are part of the same structural pattern, and that fracture sets were generated prior to Plio-Pleistocene tectonics and passively rotated. Fracture and fault length distribution was analysed by the generation of diagrams which plot cumulative frequency versus length in log–log space, normalising for area of observation. These diagrams, composed of about 30,000 measurements and constituting the most complete data set presented in the literature up till now, show that small-scale and large-scale features form part of one scale invariant system with fractal properties. No scale gap is present in our data set which comprises rock wall data in the ‘subseismic’ scale range. It appears that the 3D fracture network can best be described by a fractal dimension of 2.98 and a coefficient of 0.25. The outcome of the study places important constraints on fracture network simulation exercises in hydrocarbon reservoir simulation studies, which use numerical input parameters in order to make predictions of the tectonic texture present in the subsurface.

Three-dimensional GIS cartography applied to the study of the spatial variation of soil horizons in a Swiss floodplain

In this study, we propose to establish a framework for the study of the spatial variability of the soils found in the floodplain of the Sarine River and for the visualisation of soil distribution patterns in two- and three-dimensions (2-D, 3-D). This environment is characterised by a large lateral and vertical spatial variability of soils that corresponds to the temporal and spatial variations of the fluvial dynamics of the Sarine. The study was carried out using existing Geographical Information System (GIS) functions combined with applications specific to soil cartography. This particular GIS cartography is based on the notion of the soil horizon instead of that of the soil diagnostic profile. A Global Positioning System (GPS) survey was carried out in order to construct a local Digital Elevation Model (DEM) and to ascertain the spatial coordinates for each of the 181 soil obsevation locations. All data were stored in a GIS database, and both landform modeling and soil cartography was undertaken. GIS, ARC/INFO, and Vertical Mapper for MapInfo were adequate for our linear triangulation interpolation, for contour processing and for the creation of cross-sections as well as the corresponding vertical profiles. These vertical profiles served to illustrate the superposition of soil horizons along any line across the sampled area. A 3-D representation of soil was obtained using the quadratic finite-element method, which is generally employed in geological studies and which we adapted especially for the representation of soil horizons. 3-D cartography of this type allows the spatial pattern of a given horizon — including the variation of its thickness, the superimposition of the different soil horizons, the total soil depth, and the number of horizons at any given location — to be followed through space. Our approach, furthermore, facilitates the perception of soil horizons and their juxtarelationships as 3-D objects, and permits the visualisation of the relationships that exist between any given horizon (or sequence of horizons) and the surface topography. In thus enabling the realistic representation and easy visualisation of the spatial distribution and variability of soils in the landscape, our methodological approach provides a powerful instrument for soil scientists, and a useful decision-support tool for ecosystem management.

Interactive geovisualization of activity-travel patterns using three-dimensional geographical information systems: a methodological exploration with a large data set

A major difficulty in the analysis of disaggregate activity-travel behavior in the past arises from the many interacting dimensions involved (e.g. location, timing, duration and sequencing of trips and activities). Often, the researcher is forced to decompose activity-travel patterns into their component dimensions and focus only on one or two dimensions at a time, or to treat them as a multidimensional whole using multivariate methods to derive generalized activity-travel patterns. This paper describes several GIS-based three-dimensional (3D) geovisualization methods for dealing with the spatial and temporal dimensions of human activity-travel patterns at the same time while avoiding the interpretative complexity of multivariate pattern generalization or recognition methods. These methods are operationalized using interactive 3D GIS techniques and a travel diary data set collected in the Portland (Oregon) metropolitan region. The study demonstrates several advantages in using these methods. First, significance of the temporal dimension and its interaction with the spatial dimension in structuring the daily space-time trajectories of individuals can be clearly revealed. Second, they are effective tools for the exploratory analysis of activity diary data that can lead to more focused analysis in later stages of a study. They can also help the formulation of more realistic computational or behavioral travel models.

Development of a hybrid model for three-dimensional GIS

This paper presents a hybrid model for three-dimensional Geographical Information Systems which is an integration of surface- and volume-based models. The Triangulated Irregular Network (TIN) and octree models are integrated in this hybrid models. The TIN model works as a surface-based model which mainly serves for surface presentation and visualization. On the other hand, the octree encoding supports volumetric analysis. The designed data structure brings a major advantage in the three-dimensional selective retrieval. This technique increases the efficiency of three-dimensional data operation.

Statistical Modeling Uncertainties of Three-dimensional GIS Features

This article presents a newly developed statistical approach for modeling positional uncertainties of geometric features in three-dimensional geographical information systems (GIS). These features include points, line segments and linear features. The developed approach provides a confidence volume model for each feature type. The true locations of these measured features are included within these volumes with probability larger than a pre-defined confidence level. With the assumptions that positional errors of the two endpoints are independent and follow two three-dimensional normal distributions, the error of any point on the line segment is derived and described by the distribution of the point. The confidence volume model of a line segment is hence derived. Based on this model, the confidence volume model of linear features is further derived.

ヘリコプター搭載レーザスキャナによるＧＩＳデータベース変化部抽出と３次元化

The necessity of maximizing urban space has been fueling studies on three-dimensional (3D) geographic information systems (GIS) . Yet 3D data acquisition still relies on conventional, labor-intensive and costly photogrammetric techniques, and the data often suffers from being out-dated. This study investigates the potential of an airborne scanning laser radar system for 3D data acquisition and change detection of a 3D GIS database. Although attitude control of the helicopter still needs significant improvement for practical applications, the system proved to have the potential capability of automatically acquiring 3D information and detecting changes of 3D urban features.

The virtual reality of GIS

In this paper, I review the development of three-dimensional geographic information systems (GISs) and demonstrate how we can move beyond this to extend GIS to virtual reality. Existing elements of GIS which can imply three-dimensional representation, namely two-dimensional representation, digital elevation modeling, and visualization techniques, are first reviewed. Then it is argued that new techniques in multimedia, three-dimensional modeling and virtual reality are now at the point where they might be embodied in GIS. However, to do this, a true three-dimensional GIS must enable the following functions: realistic representation of the third dimension in data and in visualization, free movement of the user within the three-dimensional representation, normal GIS functions such as query, overlay, etc, but within three-dimensional data space, and visibility functions such as line of sight and related requirements. These ideas are then illustrated with several demonstrations being developed using new genera...

Cartographic Terrain Modeling in a Three-Dimensional GIS Environment

This paper presents a method, called cartographic terrain modeling (CTM), dealing with visualization of geographic data in an interactive, three-dimensional geographic information systems environment using selected digital terrain models, such as the triangular irregular network (TIN). One of the main features of the CTM process, next to the possibility to manipulate terrain models in three-dimensional space, is the capability to include the information of a map layer, of which the contents are represented by chains, into the three-dimensional TIN and visualize the result. The TIN is based on the Delaunay triangulation, which is applied with a conditioned chain segment split algorithm to integrate the map layer. This algorithm is explained, and results are illustrated.

GIS modelling of agricultural soil loss in a plains glacial landscape

Soil erosion on the Canadian Interior Plains is an economic and environmental problem which threatens the sustainability of annual crop production. The conventional approach to regional assessment of erosion risk is the interpretation of soil maps and evaluation of empirical soil loss equations. Use of pre-existing spatial units (quarter-sections, fields, soil map units) simplifies data storage and management, but produces very approximate models of soil landscapes, lacking the spatial resolution of the original maps. Furthermore, a dichotomy exists between the scale of erosional processes and the size of spatial unit in a typical regional study. Parameter values averaged over heterogeneous map units represent a misuse of process models derived from plot-scale experiments. This paper describes the use of a geographic information system (GIS) to model glacial landscapes and evaluate relative erosion risk at a sub-field scale over large areas. When soil and geological surveys, land cover data, and digital elevation models are combined in a GIS, landscapes can be stratified according to the dominant controls on wind and water erosion. This approach ensures geographic integrity and the best soil loss estimates with available data. Maximum use of digital geologic surveys awaits the availability of the three-dimensional GIS.