Urban Feature Extraction and Terrain Build with Large Scale Topographic Databases

The urban terrain surface is much more complex to build than mountainous regions-discontinuous, easily covered by other objects as there are high density settlements in urban area. The feature datasets in topographic databases, usually acquired and updated both by photogrammetry and field work, are helpful to build the urban terrain surface. So in the paper, a workflow of urban feature extraction and terrain build with large scale topographic databases was proposed and designed. The two dimension (2D) buildings, road and water body features were extracted from the databases with three dimension (3D) terrain features, a elevation assignment and interpolation method was presented to construct the discontinuous urban terrain surface, the relative sub-modules including feature extraction, elevation points editing, 2D to 3D, elevation interpolation and checking were developed and introduced. At last, based on the urban flood disaster analysis requirements, an experiment was carried out to verify the feasibility of this workflow and the method.