Is there a standard on types of polygons used in GADM databases? I am referring to convex, concave or general polygons, do we assume polygons to be of any one of these forms or are there restrictions?
Just polygons. No such restrictions (and it would be hard to imagine how that would work). The polygons are supposed to be valid (at least 3 unique nodes; not self-intersecting).
I just ran the Repair Geometry tool in ArcGIS9.3 on the gadm1.shp file for the whole world and there were no problems with the topology such as self-intersections of incorrect ring ordering.
Great resource you have here: Thanks for all the effort!
polygons
Just polygons. No such restrictions (and it would be hard to imagine how that would work). The polygons are supposed to be valid (at least 3 unique nodes; not self-intersecting).
topology correct
I just ran the Repair Geometry tool in ArcGIS9.3 on the gadm1.shp file for the whole world and there were no problems with the topology such as self-intersections of incorrect ring ordering.
Great resource you have here: Thanks for all the effort!
Tom Ballatore
Lake Basin Info