Looking at the maps, top edge is north, bottom south.
There is one arena map that has some of the field maps are reversed (can't remember the map name, but it's the one that has air fields at the ports). By reversed, if you were to take the map as a sheet of paper, a page, and turn the page, that would be the orientation. However top edge still remains north. So on a normal map of a small air field the runway is traveling Northeast by Southwest.
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Rokit