scapetoad.choros.chScapeToad - cartogram software by the Choros laboratory
ScapeToad uses the Gastner/Newman  diffusion-based algorithm to adapt map surfaces to user-defined variables without altering their topological relations. The software puts a regular grid over all layers (usually defined according to topographic metrics). It computes the density for each grid point. And applies the Gastner/Newman algorithm while respecting shape constraints. Map-areas now reflect user-defined variables. ScapeToad is a cross-platform, open-source application written in Java.