* Maybe add wrapper functions around rasterread and rasterwrite (for e.g., geotiff, ASCII grid, etc.).
* Add more options to mapshow.
* Implement support for projections. I (current mapping pkg maintainer) have little need nor much experience with this subject => help welcome!
* Add geodesy functions. Patches have been submitted but not yet integrated (marked  in list below). A suggested roadmap would be to integrate Felipe Nievinsky's geodesy toolbox as an upstream dependency but that toolbox needs documentation work.