Mapping and you.

Make sure you clean the map before submitting changes.

Inside your repository you will find vgstation/maptools folder. It contains 1prepare_map.bat and 2clean_map.bat . Prepare map should be run before making any changes. It makes a copy of the existing maps. Proceed and save your work. Immediately after saving, run 2clean_map.bat .

This will replace any unintended changes by merging your work with the existing map. Your changes will be ready to commit. If this process is not done, your PR will unintentionally change thousands of lines of the map and be rejected.

Da wiki

Here you will find a more thorough and maintained guide to mapping that goes beyond the submission requirements of mapping.

http://ss13.moe/wiki/index.php/Guide_to_Mapping