Service zone is used for geofencing. Devices outside of the service zone are not able to consume corrections. Multiple service zones can be applied to a service if you desire to geofence the service.
It is possible to set buffer around the zone, to avoid service discontinuity close to the boarder.
You can upload service zones to Glopos in Well known text (.wkt) format. Supported shapes are MULTIPOLYGON and POLYGON.
Some .wkt files contain shape GEOMETRYCOLLECTION representing a collection of multiple MULTIPOLYGONs and eventually other shapes. This is not supported by Glopos. Divide the file into multiple files containing only shapes of type MULTIPOLYGON or POLYGON.
Some .wkt files contain shape GEOMETRYCOLLECTION with a single MULTIPOLYGON or POLYGON. For this scenario it is safe to delete the GEOMETRYCOLLECTION in the file (together with brackets). Example: GEOMETRYCOLLECTION(POLYGON ((6 55, 6 47, 0 47, 0 55, 6 55))) can be changed to POLYGON ((6 55, 6 47, 0 47, 0 55, 6 55))