ST_GeographyFromText

Converts a Well-Known Text (WKT) string into its corresponding GEOGRAPHY object. Use this function to convert a WKT string into the format expected by the Vertica Place functions.

A GEOGRAPHY object is a spatial object with coordinates (longitude, latitude) defined on the surface of the earth. Coordinates are expressed in degrees (longitude, latitude) from reference planes dividing the earth.

The maximum size of a GEOGRAPHY object is 10 MB. If you pass a WKT to ST_GeographyFromText, the result is a spatial object whose size is greater than 10 MB, ST_GeographyFromText returns an error.

The Open Geospatial Consortium (OGC) defines the format of a WKT string in Section 7 in the Simple Feature Access Part 1 - Common Architecture specification.

Behavior type

Syntax

ST_GeographyFromText( wkt [ USING PARAMETERS ignore_errors={'y'|'n'} ] )

Arguments

wkt

Well-Known Text (WKT) string of a GEOGRAPHY object, type LONG VARCHAR

ignore_errors

(Optional) ST_GeographyFromText returns the following, based on the parameters supplied:

• NULL—If wkt is invalid and ignore_errors='y'.

• Error—If wkt is invalid and ignore_errors='n' or is unspecified.

Returns

GEOGRAPHY

Supported data types

Examples

The following example shows how to use ST_GeographyFromText.

Convert WKT into a GEOGRAPHY object:

=> CREATE TABLE wkt_ex (g GEOGRAPHY);
 CREATE TABLE
=> INSERT INTO wkt_ex VALUES(ST_GeographyFromText('POLYGON((1 2,3 4,2 3,1 2))'));
 OUTPUT
--------
      1
(1 row)