ASTEXT() — Returns the Well Known Text (WKT) representation of a GEOGRAPHY or GEOGRAPHY_POINT value.
ASTEXT( polygon | point )
The ASTEXT() function returns a text string containing a Well Known Text (WKT) representation of a GEOGRAPHY or GEOGRAPHY_POINT value. ASTEXT( value ) produces the same results as calling CAST( value AS VARCHAR).
Note that ASTEXT() does not return the identical text string that was originally input using POINTFROMTEXT() or POLYGONFROMTEXT(). When geospatial data is converted from WKT to its internal representation, the string representations of longitude and latitude are converted to double floating point values. Rounding and differing levels of precision may result in small differences in the stored values. The use of spaces and capitalization may also vary between the original input strings and the computed output of the ASTEXT() function.