IsValidDetailed (geography Data Type)
Applies to: 
SQL Server
Azure SQL Database
Azure SQL Managed Instance
Returns a message that can help to identify problems with a spatial object that is not valid. When the object is not valid, only the first error is returned. When the object is valid, a value of 24400 is returned.
Syntax
.IsValidDetailed()
Return Types
SQL Server return type: nvarchar(max)
CLR return type: string
Remarks
The following table contains possible return values:
| Return value | Description |
|---|---|
| 24400 | Valid |
| 24401 | Not valid, reason unknown. |
| 24402 | Not valid because point {0} is an isolated point, which is not valid in this type of object. |
| 24403 | Not valid because some pair of polygon edges overlap. |
| 24404 | Not valid because polygon ring {0} intersects itself or some other ring. |
| 24405 | Not valid because some polygon ring intersects itself or some other ring. |
| 24406 | Not valid because curve {0} degenerates to a point. |
| 24407 | Not valid because polygon ring {0} collapses to a line at point {1}. |
| 24408 | Not valid because polygon ring {0} is not closed. |
| 24409 | Not valid because some portion of polygon ring {0} lies in the interior of a polygon. |
| 24410 | Not valid because ring {0} is the first ring in a polygon of which it is not the exterior ring. |
| 24411 | Not valid because ring {0} lies outside the exterior ring {1} of its polygon. |
| 24412 | Not valid because the interior of a polygon with rings {0} and {1} is not connected. |
| 24413 | Not valid because of two overlapping edges in curve {0}. |
| 24414 | Not valid because an edge of curve {0} overlaps an edge of curve {1}. |
| 24415 | Not valid some polygon has an invalid ring structure. |
| 24416 | Not valid because in curve {0} the edge that starts at point {1} is either a line or a degenerate arc with antipodal endpoints. |
Examples
The following example of an invalid spatial object illustrates how the IsValidDetailed() methods behaves.
DECLARE @p GEOGRAPHY = 'Polygon((2 2, 4 4, 4 2, 2 4, 2 2))'
SELECT @p.IsValidDetailed()
--Returns: 24409: Not valid because some portion of polygon ring (1) lies in the interior of a polygon.