We describe our approach for calculating atomic planar densities for an arbitrary Miller plane in Section 2.1. When computing planar densities for multiple Miller planes and to enhance computational efficiency, we consider only the unique Miller planes with respect to crystallographic symmetry. We then cast these into the degenerate (full) representation as a post-processing step (Section 2.2). These methods have been incorporated into a Mathematica package called LatticePlane hosted at . A description of various model parameters is given in Section 2.3. Bulk downloading of Materials Project CIF files and target property data is handled via the Materials API .