STDimension (geometry Data Type)
Applies to: 
SQL Server
Azure SQL Database
Azure SQL Managed Instance
Returns the maximum dimension of a geometry instance.
Syntax
.STDimension ( )
Return Types
SQL Server return type: int
CLR return type: SqlInt32
Remarks
STDimension() returns -1 if the geometry instance is empty.
Examples
The following example creates a table variable to hold geometry instances and inserts a Point, a LineString, and a Polygon. It then uses STDimension() to return the dimensions of each geometry instance.
DECLARE @temp table ([name] varchar(10), [geom] geometry);
INSERT INTO @temp values ('Point', geometry::STGeomFromText('POINT(3 3)', 0));
INSERT INTO @temp values ('LineString', geometry::STGeomFromText('LINESTRING(0 0, 3 3)', 0));
INSERT INTO @temp values ('Polygon', geometry::STGeomFromText('POLYGON((0 0, 3 0, 0 3, 0 0))', 0));
SELECT [name], [geom].STDimension() as [dim]
FROM @temp;
The example then returns the dimensions of each geometry instance.
| name | dim |
|---|---|
| Point | 0 |
| LineString | 1 |
| Polygon | 2 |