Global urban growth monitoring by means of SAR data

In the last few decades, the increasing amount of people migrating to cities resulted in the steady spatial expansion of urban agglomerations and nowadays more than half of the world´s population currently consists of urban dwellers. Accordingly, several initiatives have been recently carried out to globally monitor the actual extent of urban areas by means of Earth observation (EO) data. In this framework, the German Aerospace Center (DLR) has recently produced a global map of built-up areas at the unique spatial resolution of 12m, namely the Global Urban Footprint (GUF). Specifically, the GUF is derived from very high resolution (VHR) SAR imagery acquired in the context of the Tan-DEM-X radar mission between 2011 and 2013. In order to map urban growth occurred in the last two decades, in this paper we adapt the approach for producing the GUF to archived ESA ERS SAR and Envisat ASAR Image Mode imagery available at 30m spatial resolution from 1991 to 2012. Preliminary experimental results assess the effectiveness of the proposed method and its potential to be employed for monitoring urban growth worldwide.