STV_Extent
Returns a bounding box containing all of the input data.
Use STV_Extent inside of a nested query for best results. The OVER clause must be empty.
Important: STV_Extent does not return a valid polygon when the input is a single point.
Behavior Type
Syntax
STV_Extent( g )
Arguments
g |
Spatial object, type GEOMETRY. |
Returns
GEOMETRY
Supported Data Types
Data Type | GEOMETRY |
Point |
Yes |
Multipoint |
Yes |
Linestring |
Yes |
Multilinestring |
Yes |
Polygon |
Yes |
Multipolygon |
Yes |
GeometryCollection |
Yes |
Examples
The following examples show how you can use STV_Extent.
Return the bounding box of a linestring, and verify that it is a valid polygon:
=> SELECT ST_AsText(geom) AS bounding_box, ST_IsValid(geom) FROM (SELECT STV_Extent(ST_GeomFromText('LineString(0 0, 1 1)')) OVER() AS geom) AS g; bounding_box | ST_IsValid -------------------------------------+------------ POLYGON ((0 0, 1 0, 1 1, 0 1, 0 0)) | t (1 row)
Return the bounding box of spatial objects in a table:
=> CREATE TABLE misc_geo_shapes (id IDENTITY, geom GEOMETRY); CREATE TABLE => COPY misc_geo_shapes (gx FILLER LONG VARCHAR, geom AS ST_GeomFromText(gx)) FROM STDIN; Enter data to be copied followed by a newline. End with a backslash and a period on a line by itself. >> POINT(-71.03 42.37) >> LINESTRING(-71.058849 42.367501, -71.062240 42.371276, -71.067938 42.371246) >> POLYGON((-71.066030 42.380617, -71.055827 42.376734, -71.060811 42.376011, -71.066030 42.380617)) >> \. => SELECT ST_AsText(geom_col) AS bounding_box FROM (SELECT STV_Extent(geom) OVER() AS geom_col FROM misc_geo_shapes) AS g; bounding_box ------------------------------------------------------------------------------------------------------------------ POLYGON ((-71.067938 42.367501, -71.03 42.367501, -71.03 42.380617, -71.067938 42.380617, -71.067938 42.367501)) (1 row)