GEMM is a plugin for MapMagic, a brilliant library for node-based procedural terrain generation. GEMM adds various generators to MapMagic in the hopes of improving its workflow and making the tackling of some situations, such as creating a forest with multiple kinds of trees, dramatically easier.
At present, GEMM allows you to more easily introduce variety into your worlds by randomising tree and object outputs, to reuse nodes through "multiplexing", thus creating smaller, nicer-looking, and easier to manage graphs. The plugin also adds support for input/output randomisation (branching graphs), provides nodes that facilitate easy mask and object hash partitioning, and you can even add little "label" nodes to remember what parts of the graph do what.
More generator nodes are planned, and I welcome suggestions on the forum thread.