The paper aims to introduce a remote sensing method to quantify urban land take, which can be used to support the quantitative objectives for limiting land take in Europe. Taking Germany as a case study, we carried out a nationwide imperviousness mapping and change detection. Based on Sentinel-2 satellite images and cloud computing platform, we applied a sub-pixel analysis approach to retrieve the imperviousness layer. This approach enables us to improve the mapping accuracy and also reduce random noise in the change detection results.