Shadow detection from VHR aerial images in urban area by using 3D city models and a decision fusion approach

In VHR(very high resolution) aerial images, shadows indicating height information are valuable for validating or detecting changes on an existing 3D city model. In the paper, we propose a novel and full automatic approach for shadow detection from VHR images. Instead of automatic thresholding, the supervised machine learning approach is...

Semantic 3D city model to raster generalisation for water run-off modelling

Water run-off modelling applied within urban areas requires an appropriate detailed surface model represented by a raster height grid. Accurate simulations at this scale level have to take into account small but important water barriers and flow channels given by the large-scale map definitions of buildings, street infrastructure, and other...

Simplified 3D city models from LiDAR

Aerial laser scan data is widely used to produce 2½D digital elevation models automatically. However, creating full 3D city models from this data is a complex task. A simplified 3D model, like a 2½D model with vertical walls will be easier to produce automatically, especially when the model is not produced to look nice, but just to give...