Popular maps will want a "mod" to be created instead of updating the original map. When in doubt, look for a map thread post maps and mods forum
- This can be done using just your web browser:
- Find the github map repo of the map you would like to update: https://github.com/triplea-maps
- Click through the maps/games folder
- Now you can edit the XML file, click the file name, and follow these instructions: http://help.github.com/articles/editing-files-in-your-repository
- When saving, github will guide you through for creating a fork, which is a remote copy that you own. From that you can request changes in your 'fork' to be 'merged' back in to the main map repository.
- This will lead to the creation of a pull request. Map admins and or map owners will review the change and will then either comment on it requesting clarification or updates, or they will merge it.
- Similar to updating files, the github website will allow you to do this. To do it in bulk you may need to do some git. Github desktop from github is a pretty easy tool, there is also Git for Windows, source tree which are other good git clients.