STAsText

STAsText is a method associated with SQL Server’s spatial data types, specifically geometry and geography. It returns the Well-Known Text (WKT) representation of a spatial value as a string, making the shape’s structure readable in text form.

Usage and syntax

STAsText is invoked as a method on a spatial value, with no parameters. For example: geometryColumn.STAsText() or geographyValue.STAsText(). The result is a string containing the WKT, such as "POINT (30 10)" or "LINESTRING (30 10, 10 30, 40 40)".

Return value and behavior

The method returns the WKT description of the geometry or geography object. For empty geometries, the text reflects emptiness, e.g., "POINT EMPTY" or "GEOMETRYCOLLECTION EMPTY". The exact string conveys the type, coordinates, and structure of the spatial value, independent of the underlying binary representation.

Context and usage

STAsText is commonly used for exporting, displaying, or interoperating with systems that consume WKT. It is the textual counterpart to STAsBinary, which returns Well-Known Binary (WKB). The output is influenced by the underlying spatial type: geometry uses planar coordinates, while geography uses a geographic coordinate system (typically longitude and latitude).

Notes

The SRID is a property of the spatial value but is not embedded in the WKT returned by STAsText; the SRID can be accessed separately if needed. STAsText is supported in SQL Server’s spatial types since the introduction of geometry and geography types in SQL Server 2008 and remains a standard method for text-based spatial representation. See also STAsBinary for the binary representation.