Provide a radius attribute for the dgml target tag
completed by: Illya Kovalevskyy
mentors: Torsten Rahn, Dennis Nienhüser
Currently if you load a map of a Jupiter or Saturn moon then measuring distances returns bogus values: currently the radius of the moon does not get specified so the radius of the earth is assumed instead. In order to fix this a radius attribute for the target tag should be introduced and parsed.The radius should get properly assigned to the actual radius of the globe. As an example the map of mimas should be adjusted so that this works properly.