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:
|
Returns
GEOGRAPHY
Supported Data Types
Data Type | GEOGRAPHY (Perfect Sphere) | GEOGRAPHY (WGS84) |
Point | Yes | Yes |
Multipoint |
Yes |
Yes |
Linestring |
Yes |
Yes |
Multilinestring |
Yes |
Yes |
Polygon |
Yes |
Yes |
Multipolygon |
Yes |
Yes |
GeometryCollection |
No |
No |
Example
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)