Terrain skeleton lines, among the most significant elements of topographical maps, are the valley lines that connect the deepest points of valleys, and the ridge lines that connect the highest points of ridges. In order to obtain correct and enough information about land forms from a topographical map, skeleton lines have to be considered and portrayed together with contours. Their extraction h...

Interpolation of digital elevation models becomes necessary in many situations, for instance, when constructing them from contour lines (available e.g., from nondigital cartography), or from disparity maps based on pairs of stereoscopic views, which often leaves large areas where point correspondences cannot be found reliably. The absolutely minimizing Lipschitz extension (AMLE) model is single...

For regional models, the shallow water table surface is often used as a source/sink boundary condition, as model grid scale precludes simulation of the water table aquifer. This approach is appropriate when the water table surface is relatively stationary. Since water table surface maps are not readily available, the elevation of the water table used in model cells is estimated via a two-step p...

The paper presents the results of an accuracy analysis of a number of gridded Digital Surface Models (DSMs) which have been created from first return laser scanning (LiDAR) data. DSMs are created using a variety of methods, and differences between the models and the raw LiDAR data are quantified and the spatial patterns of the errors explored. The results presented in this paper demonstrate the...

We consider the problem of interpolating a surface based on sparse data such as individual points or level lines. We derive interpolators satisfying a list of desirable properties with an emphasis on preserving the geometry and characteristic features of the contours while ensuring smoothness across level lines. We propose an anisotropic third-order model and an efficient method to adaptively e...

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This paper describes methods that use digital elevation models (DEMs) in hydrology, implemented as an ArcGIS toolbar using Visual Basic and the ESRI object library. I describe generalized channel network delineation to objectively estimate drainage density and by using terrain curvature accommodate spatially variable drainage density. The multiple flow direction field determined from a DEM also...

This paper explores a methodology for quantifying the uncertainty of DEMs created by digitising topographic maps. The origins of uncertainty in DEM production were identified and examined. The uncertainty of DEM data was quantified by computing a vector total of Root Mean Square Error (RMSE) from the source map, sampling and measurement errors, and the interpolation process. Distributional meas...

Methods for identifying the size, or scale, of hillslopes and the extent of channel networks from digital elevation models (DEMs) are examined critically. We show that a constant critical support area, the method most commonly used at present for channel network extraction from DEMs, is more appropriate for depicting the hillslope/valley transition than for identifying channel heads. Analysis o...