Urban Footprint Processor—Fully Automated Processing Chain Generating Settlement Masks From Global Data of the TanDEM-X Mission

TLDR

TanDEM‑X provides very high resolution SAR imagery from 2011‑2013 that uniquely enables identification of built‑up areas worldwide. This letter introduces a fully automated processing system for delineating human settlements globally from TanDEM‑X data. The Urban Footprint Processor extracts texture, applies an unsupervised classification combining backscatter and texture, and then post‑edits and mosaics the results to produce a binary settlement layer. Experimental results demonstrate that the UFP yields highly accurate geo‑data, improving the global mapping of human settlements.

Abstract

The German TerraSAR-X add-on for Digital Elevation Measurement (TanDEM-X) mission (TDM) collects two global data sets of very high resolution (VHR) synthetic aperture radar (SAR) images between 2011 and 2013. Such imagery provides a unique information source for the identification of built-up areas in a so far unique spatial detail. This letter presents the novel implementation of a fully automated processing system for the delineation of human settlements worldwide based on the SAR data acquired in the context of the TDM. The proposed Urban Footprint Processor (UFP) includes three main processing stages dedicated to: i) the extraction of texture information suitable for highlighting regions characterized by highly structured and heterogeneous built-up areas; ii) the generation of a binary settlement layer (built-up, non-built-up) based on an unsupervised classification scheme accounting for both the original backscattering amplitude and the extracted texture; and iii) a final post-editing and mosaicking phase aimed at providing the final Urban Footprint (UF) product for arbitrary geographical regions. Experimental results assess the high potential of the TDM data and the proposed UFP to provide highly accurate geo-data for an improved global mapping of human settlements.