I am working on an application, where the user can place some items on a map. Some of these items have a direction, currently saved as radians where 0 is towards right/east. We want to enable the user to batch add items via some kind of spreadsheet, and we became unsure if this "0 means towards right" is meaningful. When I look at a compass, 0 means towards north.
Do you know if there is an established direction standard in GIS, for example that 0 (radians or degrees) should always mean north (or east)?