If you have created catchment areas in another software, and you wish to be able to retrieve them in OALLEY, the import function of the zones will allow you to do so without having to recreate them.
OALLEY allows you to easily import zones in KML format.
To do this, go to the map, then drag and drop your file directly onto the map:
The zone(s) from the KML file will appear on the map, and will be added to the active layer.
To go further: