rendermap is a tool used to render PNG images of Minecraft ingame map data at various scales (TODO!)
Assuming libcppnbt is in the current working directory (either as static or shared library or symlinked), libz and libpng either installed globally or similar to libcppnbt, running 'make' will do the job. Otherwise minor modification to the Makefile will have to be done to include the correct search paths.
Running 'make' will create an executable file called "rendermap".
$ rendermap Map_0.dat # This will create the image "Map_0.dat.png" in the current directory