在DB2中,它也是一个多边形。看起来你正在存储网格,所以一个快速的检查可以是,如果ST_ENVELOPE(geometry) == geometry,那么你有一个正方形。
这段代码来自于:
DB2的文档
SET CURRENT PATH = CURRENT PATH, db2gse;
CREATE TABLE sample_geoms (id INTEGER, geometry ST_Geometry);
INSERT INTO sample_geoms VALUES
(1, ST_Geometry(ST_Point('point EMPTY',0)));
INSERT INTO sample_geoms VALUES
(2, ST_Geometry(ST_Point('point zm (10 10 16 30)' ,0)));
INSERT INTO sample_geoms VALUES
(3, ST_Geometry(ST_Multipoint('multipoint m (10 10 5, 50 10 6,
10 30 8)' ,0)));
INSERT INTO sample_geoms VALUES
(4, ST_Geometry(ST_Linestring('linestring (10 10, 20 10)',0)));
INSERT INTO sample_geoms VALUES
(5, ST_Geometry(ST_Polygon('polygon((40 120, 90 120, 90 150,
40 150, 40 120))',0)));
SELECT id, CAST(ST_AsText(ST_Envelope(geometry)) as VARCHAR(160)) Envelope
FROM sample_geoms;
结果:
ID ENVELOPE
----------- ---------------------------------------------------------------
1 -
2 POLYGON (( 9 9, 11 9, 11 11, 9 11, 9 9))
3 POLYGON (( 10 10, 50 10, 50 30, 10 30, 10 10))
4 POLYGON (( 10 9, 20 9, 20 11, 10 11, 10 9))
5 POLYGON (( 40 120, 90 120, 90 150, 40 150, 40 120))
看到ID = 5了吗?最后一个POLYGON等于ST_ENVELOPE(geometry)