The DEM & Spatial Hydrology Extension  contains plugins that extend the functionality of the WhiteboxTools open-core for advanced digital elevation model (DEM) processing and hydrological analysis. This extension contains numerous tools for calculating surface curvatures, such as unsphericity curvature, difference curvature, and rotor. This extension easily integrates into your current WhiteboxTools environment. To utilize the DEM & Spatial Hydrology Extension, purchase a software license, then download and install the extension. The extension has transparent pricing, with academic and multi-seat discounts. We offer both annual and perpetual licenses. By purchasing a license you are not only enhancing the power of the open-source WhiteboxTools platform, you are also helping to support the continued development of the software.