Relief Form — Anthropogenic Forms (25 m Grid Data) (WMS Service)

A laser DGM contains all anthropogenic changes in the Earth’s surface. While building surfaces are already identified by the manufacturers of the laser DGM and interpolated on the basis of neighbouring heights, traffic buildings (e.g. road and railway dams) are particularly problematic. A basic prerequisite for relief analysis to support the calculation of surface processes (outflow paths, above-ground catchment areas) is therefore the use of a DGM in which the anthropogenic relief forms are identified and removed as far as possible. For this purpose, a filter was developed to identify anthropogenic relief forms (Köthe & Bock 2009). The procedure is quite complex and is based, among other things, on the detection of dam crowns and the identification of terrain bucklings (as the basis of the dams). The basic assumption is that each dam has a dam crown and usually sits sharply off the surrounding area at its base. The simple height difference between a DGM with anthropogenic relief forms and a DGM, in which all local maxima and minima have been eliminated, already provides very good indication of the location of anthropogenic relief forms. Köthe, R. & Bock, M. (2009) Preprocessing of Digital Elevation Models — derived from Laser Scanning and Radar Interferometry — for Terrain Analysis in Geosciences. — Proceedings of Geomorphometry, Zurich, Switzerland, 31 August — 2 September: PP. 155-161; Zurich. http://www.geomorphometry.org/system/files/koethe2009geomorphometry.pdf激光数字地面模型（Laser Digital Ground Model, DGM）涵盖了地球表面所有人为改造引发的地表变化。尽管该数字地面模型的生产厂商已识别出建筑物地表，并基于相邻高程值完成插值，但交通构筑物（如道路路堤、铁路路堤）的识别仍是尤为棘手的难题。 若要开展支撑地表过程（径流路径、地面集水区）计算的地形分析，其基本前提是使用已尽可能识别并移除人为地形形态的数字地面模型。为此，研究人员开发了一款用于识别人为地形形态的滤波器（Köthe & Bock, 2009）。该处理流程颇为复杂，其技术依据涵盖对堤顶的检测，以及对作为路堤基础的地形隆起（terrain bucklings）的识别。其基本假设为：每一处路堤均存在堤顶，且其基底通常与周边区域存在显著的高程落差。将包含人为地形形态的数字地面模型与已移除所有局部极大、极小值的数字地面模型进行简单的高程差计算，即可较为精准地定位人为地形形态的分布位置。 Köthe, R. 与 Bock, M. (2009) 《用于地球科学地形分析的激光扫描与雷达干涉测量数字高程模型预处理》，载于《地貌测量学会议论文集》，瑞士苏黎世，8月31日—9月2日：第155-161页；苏黎世。http://www.geomorphometry.org/system/files/koethe2009geomorphometry.pdf