Digital terrain representation. Data Acquisition Methodology. Terrain Surface Modeling (Reconstruction). Algorithms for Triangular Irregular Network Formation. Interpolation Methods. Data Quality Control. Mathematical Models for DTM Accuracy.Multi-Scale Representation of Digital Elevation Models. DTM Data Management. Contouring from DTM. DTM-Based Terrain Analysis (DTM Interpretation). Visualization of DTM Surface. Applications. Integration with GIS. Index.

Digital Terrain Modeling: Principles and Methodology

The Delaunay triangulation is commonly used to generate triangulated irregular network (TIN) models for a best description of the surface morphology in a variety of applications in geographic information systems (GIS). This paper discusses the definitions and basic properties of the standard and constrained Delaunay triangulations. Several existing Delaunay algorithms are reviewed and classified into three categories according to their procedures: (1) divide-and-conquer methods, (2) incremental insertion methods, and (3) triangulation growth methods. Furthermore, a linear-time Convex Hull Insertion algorithm is presented to construct TINs for a set of points as well as specific features such as constraint breaklines and exclusion boundaries. Empirical results over various sets of up to 50000 points on personal computers show that the proposed algorithm efficiently expedites the construction of TIN models in approximately O(N) for N randomly distributed points.

Delaunay triangulations in TIN creation: an overview and a linear-time algorithm

An object-specific image-texture analysis of H-resolution forest imagery☆

This book covers fundamental aspects of spatial data modelling specifically on the aspect of three-dimensional (3D) modelling and structuring. Realisation of true 3D GIS spatial system needs a lot of efforts, and the process is taking place in various research centres and universities in some countries. The development of spatial data modelling for 3D objects is the focus of this book. The book begins with some problems and motivations, the fundamental theories, the implementation, and some applications developed based on the concepts. The book is intended for various geoinformation related professionals like GIS engineers, GIS software developers, photogrammetrists, land surveyors, mapping specialists, researchers, postgraduate students, and lecturers.

Spatial Data Modelling for 3D GIS

We study the influence of nine local, non-local and combined quantitative topographic characteristics on vegetation cover, altitude and density. The objects under study are four areas of the Rudny Altai. Differentiation of plant properties is shown to depend on relief parameters which control migration and accumulation of water in landscape by gravity. These are landsurface curvatures, catchment area, topographic and stream power indexes. In some cases the phytocoenosis characteristics can have higher correlation with non-local and combined topographic variables than with local ones. This derives from the fact that non-local and combined relief attributes take into account a relative location of an area in a landscape, so they can better determine topographic prerequisites of substance motion. We demonstrate the advisability of the use of digital models and maps of indicated topographic characteristics in plant investigations.

Influence of topography on some vegetation cover properties

The problems of developing an efficient Delaunay triangulation algorithm are described and a number of modifications to existing algorithms suggested. The process of triangle creation is related to that of isarithmic mapping. Estimates of relative time savings are given using a grid versus a triangular data base.

Delaunay Triangulation of a Random Data Set for Isarithmic Mapping

This paper is an attempt to determine the average geography academic's needs in relation to his research requirements and computing knowledge in automated map production. Usually he will not be attempting to produce a final map, but probably only one to enable him to analyse his data with more accuracy. An outline is given of what the user can expect from a plotting system, and also what he will have to know to benefit from the results produced. The problem of contouring is taken as a demonstration of the difficulties involved. Examples are given to show that no computer contour map can be considered objective, and that the results produced are determined by the contouring method employed combined with the skill of the user.

Michael J. McCullagh

Papers

Delaunay Triangulation of a Random Data Set for Isarithmic Mapping

User Desires and Graphics Capability in the Academic Environment