I have a table which include geography(polygon) type.
CREATE TABLE place ( name varchar(100), geom GEOMETRY(POLYGON, 4326) ); insert into place SELECT 'place1', ST_GeomFromText('POLYGON((-71.1776585052917 42.3902909739571,-71.1776820268866 42.3903701743239, -71.1776063012595 42.3903825660754,-71.1775826583081 42.3903033653531,-71.1776585052917 42.3902909739571))',4326);
I want to know following points of geometry(polygon)
- most north point
- most south point
- most east point
- most west point
( This seems to be commonly called "extreme point")
For example, in the above image, the coordinates (x, y) of the four corners of the rectangle are the information I want to know. (But my applications data is not true rectangle.that has more corner.)
I checked document, I couldn't find suitable function.
How can I get or calculate extreme points using SQL?