ST_Dimension

定义

ST_Dimension 用于返回几何对象的维度。在这种情况下，维度是指长度和宽度。例如，点既没有长度也没有宽度，所以其维度为 0；而线只有长度却没有宽度，因此其维度为 1。

语法

Oracle 和 PostgreSQL

sde.st_dimension (geometry1 sde.st_geometry)

SQLite

st_dimension (geometry1 geometryblob)

返回类型

整型

示例

创建包含 geotype 和 g1 两列的 dimension_test 表。geotype 列存储的是 g1 几何列中所存储的子类的名称。

SELECT 语句列出了 geotype 列中所存储的子类名称以及相应几何类型的维度。

Oracle

CREATE TABLE dimension_test (
 geotype varchar(20),
 g1 sde.st_geometry
);

INSERT INTO DIMENSION_TEST VALUES (
 'Point',
 sde.st_pointfromtext ('point (10.02 20.01)', 4326)
);

INSERT INTO DIMENSION_TEST VALUES (
 'Linestring',
 sde.st_linefromtext ('linestring (10.02 20.01, 10.32 23.98, 11.92 25.64)', 4326)
);

INSERT INTO DIMENSION_TEST VALUES (
 'Polygon',
 sde.st_polyfromtext ('polygon ((10.02 20.01, 11.92 35.64, 25.02 34.15, 19.15 33.94, 10.02 20.01))', 4326)
);

INSERT INTO DIMENSION_TEST VALUES (
 'Multipoint',
 sde.st_mpointfromtext ('multipoint (10.02 20.01, 10.32 23.98, 11.92 25.64)', 4326)
);

INSERT INTO DIMENSION_TEST VALUES (
 'Multilinestring',
 sde.st_mlinefromtext ('multilinestring ((10.02 20.01, 10.32 23.98, 11.92 25.64), (9.55 23.75, 15.36 30.11))', 4326)
);

INSERT INTO DIMENSION_TEST VALUES (
 'Multipolygon',
 sde.st_mpolyfromtext ('multipolygon (((10.02 20.01, 11.92 35.64, 25.02 34.15,
19.15 33.94, 10.02 20.01), (51.71 21.73, 73.36 27.04, 71.52 32.87,
52.43 31.90, 51.71 21.73)))', 4326)
);

SELECT geotype, sde.st_dimension (g1) Dimension
 FROM DIMENSION_TEST;

GEOTYPE                    Dimension

Point                       0
Linestring                  1
Polygon                     2
Multipoint                  0
Multilinestring             1
Multipolygon                2

PostgreSQL

CREATE TABLE dimension_test (
 geotype varchar(20),
 g1 sde.st_geometry
);

INSERT INTO dimension_test VALUES (
 'Point',
 sde.st_point ('point (10.02 20.01)', 4326)
);

INSERT INTO dimension_test VALUES (
 'Linestring',
 sde.st_linestring ('linestring (10.02 20.01, 10.32 23.98, 11.92 25.64)', 4326)
);

INSERT INTO dimension_test VALUES (
 'Polygon',
 sde.st_polygon ('polygon ((10.02 20.01, 11.92 35.64, 25.02 34.15, 19.15 33.94, 10.02 20.01))', 4326)
);

INSERT INTO dimension_test VALUES (
 'Multipoint',
 sde.st_multipoint ('multipoint (10.02 20.01, 10.32 23.98, 11.92 25.64)', 4326)
);

INSERT INTO dimension_test VALUES (
 'Multilinestring',
 sde.st_multilinestring ('multilinestring ((10.02 20.01, 10.32 23.98, 11.92 25.64), (9.55 23.75, 15.36 30.11))', 4326)
);

INSERT INTO dimension_test VALUES (
 'Multipolygon',
 sde.st_multipolygon ('multipolygon (((10.02 20.01, 11.92 35.64, 25.02 34.15,
19.15 33.94, 10.02 20.01), (51.71 21.73, 73.36 27.04, 71.52 32.87,
52.43 31.90, 51.71 21.73)))', 4326)
);

SELECT geotype, sde.st_dimension (g1) 
 AS Dimension
 FROM dimension_test;

geotype                  dimension

Point                       0
Linestring                  1
Polygon                     2
Multipoint                  0
Multilinestring             1
Multipolygon                2

SQLite

CREATE TABLE dimension_test (
 geotype varchar(20)
);

SELECT AddGeometryColumn (
 NULL,
 'dimension_test',
 'g1',
 4326,
 'geometry',
 'xy',
 'null'
);

INSERT INTO dimension_test VALUES (
 'Point',
 st_point ('point (10.02 20.01)', 4326)
);

INSERT INTO dimension_test VALUES (
 'Linestring',
 st_linestring ('linestring (10.02 20.01, 10.32 23.98, 11.92 25.64)', 4326)
);

INSERT INTO dimension_test VALUES (
 'Polygon',
 st_polygon ('polygon ((10.02 20.01, 11.92 35.64, 25.02 34.15, 19.15 33.94, 10.02 20.01))', 4326)
);

INSERT INTO dimension_test VALUES (
 'Multipoint',
 st_multipoint ('multipoint (10.02 20.01, 10.32 23.98, 11.92 25.64)', 4326)
);

INSERT INTO dimension_test VALUES (
 'Multilinestring',
 st_multilinestring ('multilinestring ((10.02 20.01, 10.32 23.98, 11.92 25.64), (9.55 23.75, 15.36 30.11))', 4326)
);

INSERT INTO dimension_test VALUES (
 'Multipolygon',
 st_multipolygon ('multipolygon (((10.02 20.01, 11.92 35.64, 25.02 34.15,
19.15 33.94, 10.02 20.01), (51.71 21.73, 73.36 27.04, 71.52 32.87,
52.43 31.90, 51.71 21.73)))', 4326)
);

SELECT geotype, st_dimension (g1) 
 AS "Dimension"
 FROM dimension_test;

geotype                  Dimension

Point                       0
Linestring                  1
Polygon                     2
Multipoint                  0
Multilines                  1
Multipolyg                  2