Comparing actual and predicted activity values with CheS-Mapper. The CPDB hamster dataset is embedded into 3D space, based on 14 physico-chemical (PC) descriptors that have been computed with CheS-Mapper using Open Babel. The compounds are predicted with a 3-Nearest Neighbor approach employing the same PC features. The inner sphere corresponds to the actual endpoint activity, with class values active (red) and inactive (blue). The outer, flattened spheroid depicts the prediction.