The World Settlement Footprint (WSF) 2015 is a 10m resolution binary mask outlining the extent of human settlements globally derived by means of 2014-2015 multitemporal Landsat-8 and Sentinel-1 imagery (of which ~217,000 and ~107,000 scenes have been processed, respectively).
In particular, the rationale is that the temporal dynamics of human settlements over time are sensibly different than those of all other non-settlement information classes. Hence, given all the multitemporal images available over a region of interest in the selected time interval, key temporal statistics (i.e., temporal mean, minimum, maximum, etc.) are extracted for:
a) the original backscattering value in the case of radar data; and
b) different spectral indices (e.g., vegetation index, built-up index, etc.) derived after performing cloud masking in the case of optical imagery.
Next, different classification schemes based on Support Vector Machines (SVMs) are separately applied to the optical and radar temporal features, respectively, and, finally, the two outputs are properly combined together. To quantitatively assess the high accuracy and reliability of the layer, an extensive validation exercise has been carried out in collaboration with Google based on a huge amount of ground-truth samples (i.e., 900,000) labelled by crow-sourcing photointerpretation. In particular, a statistically robust and transparent protocol has been defined following the state-of-the-art practices currently recommended in the literature. For all technical details, please refer to our Publication
Product Version: 2.0 Coverage: global Resolution: 10 m x 10 m
Attribution: WSF2015 Data are licensed under: Attribution 4.0 International (CC BY 4.0)