STIsValid (geography Data Type)
Returns true if a geography instance is well-formed and recognized as a valid geography object based on its Open Geospatial Consortium (OGC) type. Returns false if a geography instance is not well-formed. This method is precise.
This geography data type method supports FullGlobe instances or spatial instances that are larger than a hemisphere.
The OGC type of a geography instance can be determined by invoking STGeometryType().
SQL Server produces only valid geography instances, but allows for the storage and retrieval of invalid instances. A valid instance representing the same point set of an invalid instance can be retrieved using the MakeValid() method.
The following example creates a geography instance and uses STIsValid() to test if the instance is valid.
DECLARE @g geography = geography::STGeomFromText('LINESTRING(0 0, 2 2, 1 0)', 4326); SELECT @g.STIsValid(); DECLARE @g geography