空间对象关系函数
ST_3DClosestPoint
描述
返回几何对象g1之中，离几何对象g2最近的坐标点。
函数声明
geometry ST_3DClosestPoint(geometry g1, geometry g2);
使用示例
SELECT ST_AsEWKT(ST_3DClosestPoint(line,pt)) AS cp3d_line_pt,ST_AsEWKT(ST_ClosestPoint(line,pt)) As cp2d_line_ptFROM (SELECT 'POINT(100 100 30)'::geometry As pt,'LINESTRING (20 80 20, 98 190 1, 110 180 3, 50 75 1000)'::geometry As line) As foo;cp3d_line_pt | cp2d_line_pt-----------------------------------------------------------+------------------------------------------POINT(54.6993798867619 128.935022917228 11.5475869506606) | POINT(73.0769230769231 115.384615384615)
ST_3DDistance
描述
返回给定两个几何对象的3维笛卡尔积距离（基于参考坐标系的）。
函数声明
float ST_3DDistance(geometry g1, geometry g2);
使用示例
-- Geometry example - units in meters (SRID: 2163 US National Atlas Equal area) (3D point and line compared 2D point and line)-- Note: currently no vertical datum support so Z is not transformed and assumed to be same units as final.SELECT ST_3DDistance(ST_Transform(ST_GeomFromEWKT('SRID=4326;POINT(-72.1235 42.3521 4)'),2163),ST_Transform(ST_GeomFromEWKT('SRID=4326;LINESTRING(-72.1260 42.45 15, -72.123 42.1546 20)'),2163)) As dist_3d,ST_Distance(ST_Transform(ST_GeomFromText('POINT(-72.1235 42.3521)',4326),2163),ST_Transform(ST_GeomFromText('LINESTRING(-72.1260 42.45, -72.123 42.1546)', 4326),2163)) As dist_2d;dist_3d | dist_2d------------------+-----------------127.295059324629 | 126.66425605671
ST_3DDWithin
描述
对于两个3D（Z）几何对象，如果两者的距离在给定的单位之内，则返回true。
函数声明
boolean ST_3DDWithin(geometry g1, geometry g2, double precision distance_of_srid);
使用示例
-- Geometry example - units in meters (SRID: 2163 US National Atlas Equal area) (3D point and line compared 2D point and line)-- Note: currently no vertical datum support so Z is not transformed and assumed to be same units as final.SELECT ST_3DDWithin(ST_Transform(ST_GeomFromEWKT('SRID=4326;POINT(-72.1235 42.3521 4)'),2163),ST_Transform(ST_GeomFromEWKT('SRID=4326;LINESTRING(-72.1260 42.45 15, -72.123 42.1546 20)'),2163),126.8) As within_dist_3d,ST_DWithin(ST_Transform(ST_GeomFromEWKT('SRID=4326;POINT(-72.1235 42.3521 4)'),2163),ST_Transform(ST_GeomFromEWKT('SRID=4326;LINESTRING(-72.1260 42.45 15, -72.123 42.1546 20)'),2163),126.8) As within_dist_2d;within_dist_3d | within_dist_2d----------------+----------------f | t
ST_3DDFullyWithin
描述
如果两个3D几何对象相互距离完全落在给定的范围之内，则返回true。
函数声明
boolean ST_3DDFullyWithin(geometry g1, geometry g2, double precision distance);
使用示例
-- This compares the difference between fully within and distance within as well-- as the distance fully within for the 2D footprint of the line/point vs. the 3d fully withinSELECT ST_3DDFullyWithin(geom_a, geom_b, 10) as D3DFullyWithin10, ST_3DDWithin(geom_a, geom_b, 10) as D3DWithin10,ST_DFullyWithin(geom_a, geom_b, 20) as D2DFullyWithin20,ST_3DDFullyWithin(geom_a, geom_b, 20) as D3DFullyWithin20 from(select ST_GeomFromEWKT('POINT(1 1 2)') as geom_a,ST_GeomFromEWKT('LINESTRING(1 5 2, 2 7 20, 1 9 100, 14 12 3)') as geom_b) t1;d3dfullywithin10 | d3dwithin10 | d2dfullywithin20 | d3dfullywithin20------------------+-------------+------------------+------------------f | t | t | f
ST_3DIntersects
描述
如果给定的几何对象在3D空间内相交，则返回true。
函数声明
boolean ST_3DIntersects(geometry geomA, geometry geomB);
使用示例
SELECT ST_3DIntersects(pt, line), ST_Intersects(pt,line)FROM (SELECT 'POINT(0 0 2)'::geometry As pt,'LINESTRING (0 0 1, 0 2 3 )'::geometry As line) As foo;st_3dintersects | st_intersects-----------------+---------------f | t(1 row)
ST_3DLongestLine
描述
返回两个几何对象在3维空间中的最长线段。
函数声明
geometry ST_3DLongestLine(geometry g1, geometry g2);
使用示例
SELECT ST_AsEWKT(ST_3DLongestLine(line,pt)) AS lol3d_line_pt,ST_AsEWKT(ST_LongestLine(line,pt)) As lol2d_line_ptFROM (SELECT 'POINT(100 100 30)'::geometry As pt,'LINESTRING (20 80 20, 98 190 1, 110 180 3, 50 75 1000)'::geometry As line) As foo;lol3d_line_pt | lol2d_line_pt-----------------------------------+----------------------------LINESTRING(50 75 1000,100 100 30) | LINESTRING(98 190,100 100)
ST_3DMaxDistance
描述
返回给定的两个几何对象在3维空间中的最远距离。
函数声明
float ST_3DMaxDistance(geometry g1, geometry g2);
使用示例
-- Geometry example - units in meters (SRID: 2163 US National Atlas Equal area) (3D point and line compared 2D point and line)-- Note: currently no vertical datum support so Z is not transformed and assumed to be same units as final.SELECT ST_3DMaxDistance(ST_Transform(ST_GeomFromEWKT('SRID=4326;POINT(-72.1235 42.3521 10000)'),2163),ST_Transform(ST_GeomFromEWKT('SRID=4326;LINESTRING(-72.1260 42.45 15, -72.123 42.1546 20)'),2163)) As dist_3d,ST_MaxDistance(ST_Transform(ST_GeomFromEWKT('SRID=4326;POINT(-72.1235 42.3521 10000)'),2163),ST_Transform(ST_GeomFromEWKT('SRID=4326;LINESTRING(-72.1260 42.45 15, -72.123 42.1546 20)'),2163)) As dist_2d;dist_3d | dist_2d------------------+------------------24383.7467488441 | 22247.8472107251
ST_3DShortestLine
描述
返回两个几何对象在3维空间中的最短线段。
函数声明
geometry ST_3DShortestLine(geometry g1, geometry g2);
使用示例
SELECT ST_AsEWKT(ST_3DShortestLine(line,pt)) AS shl3d_line_pt,ST_AsEWKT(ST_ShortestLine(line,pt)) As shl2d_line_ptFROM (SELECT 'POINT(100 100 30)'::geometry As pt,'LINESTRING (20 80 20, 98 190 1, 110 180 3, 50 75 1000)'::geometry As line) As foo;shl3d_line_pt | shl2d_line_pt----------------------------------------------------------------------------+------------------------------------------------------LINESTRING(54.6993798867619 128.935022917228 11.5475869506606,100 100 30) | LINESTRING(73.0769230769231 115.384615384615,100 100)
ST_Area
描述
返回给定Polygon或MultiPolygon的表面积。如果是一个几何对象，则返回其SRID指定的坐标参考系下的笛卡尔面积。对于地理对象，返回其在球面上的面积，以平方米为单位。
函数声明
float ST_Area(geometry g1);float ST_Area(geography geog, boolean use_spheroid=true);
使用示例
SELECT ST_Area(the_geom) As sqft, ST_Area(the_geom)*POWER(0.3048,2) As sqmFROM (SELECTST_GeomFromText('POLYGON((743238 2967416,743238 2967450,743265 2967450,743265.625 2967416,743238 2967416))',2249) ) As foo(the_geom);sqft | sqm---------+-------------928.625 | 86.27208552
ST_Azimuth
描述
返回从坐标点A到坐标点B的方位角，以北方为基准往顺时针方向旋转。
函数声明
float ST_Azimuth(geometry pointA, geometry pointB);float ST_Azimuth(geography pointA, geography pointB);
使用示例
SELECT degrees(ST_Azimuth(ST_Point(25, 45), ST_Point(75, 100))) AS degA_B,degrees(ST_Azimuth(ST_Point(75, 100), ST_Point(25, 45))) AS degB_A;dega_b | degb_a------------------+------------------42.2736890060937 | 222.273689006094
ST_Angle
描述
返回三个坐标点，或两个向量（四个坐标点或两条线）之间的夹角。
函数声明
float ST_Angle(geometry point1, geometry point2, geometry point3, geometry point4);float ST_Angle(geometry line1, geometry line2);
使用示例
WITH rand AS (SELECT s, random() * 2 * PI() AS rad1, random() * 2 * PI() AS rad2FROM generate_series(1,2,2) AS s), points AS (SELECT s, rad1,rad2, ST_MakePoint(cos1+s,sin1+s) as p1, ST_MakePoint(s,s) AS p2, ST_MakePoint(cos2+s,sin2+s) as p3FROM rand,cos(rad1) cos1, sin(rad1) sin1,cos(rad2) cos2, sin(rad2) sin2)SELECT s, ST_AsText(ST_SnapToGrid(ST_MakeLine(ARRAY[p1,p2,p3]),0.001)) AS line, degrees(ST_Angle(p1,p2,p3)) as computed_angle, round(degrees(2*PI()-rad2 -2*PI()+rad1+2*PI()))::int%360 AS reference, round(degrees(2*PI()-rad2 -2*PI()+rad1+2*PI()))::int%360 AS referenceFROM points ;1 | line | computed_angle | reference------------------+------------------1 | LINESTRING(1.511 1.86,1 1,0.896 0.005) | 155.27033848688 | 155
ST_Centroid
描述
返回给定几何对象或地理对象的形心。
函数声明
geometry ST_Centroid(geometry g1);geography ST_Centroid(geography g1, boolean use_spheroid=true);
使用示例
SELECT ST_AsText(ST_Centroid('MULTIPOINT ( -1 0, -1 2, -1 3, -1 4, -1 7, 0 1, 0 3, 1 1, 2 0, 6 0, 7 8, 9 8, 10 6 )'));st_astext------------------------------------------POINT(2.30769230769231 3.30769230769231)(1 row)SELECT ST_AsText(ST_centroid(g))FROM ST_GeomFromText('CIRCULARSTRING(0 2, -1 1,0 0, 0.5 0, 1 0, 2 1, 1 2, 0.5 2, 0 2)') AS g ;------------------------------------------POINT(0.5 1)SELECT ST_AsText(ST_centroid(g))FROM ST_GeomFromText('COMPOUNDCURVE(CIRCULARSTRING(0 2, -1 1,0 0),(0 0, 0.5 0, 1 0),CIRCULARSTRING( 1 0, 2 1, 1 2),(1 2, 0.5 2, 0 2))' ) AS g;------------------------------------------POINT(0.5 1)
ST_ClosestPoint
描述
返回几何对象g1之中，离几何对象g2最近的坐标点。
函数声明
geometry ST_ClosestPoint(geometry g1, geometry g2);
使用示例
SELECT ST_AsText(ST_ClosestPoint(pt,line)) AS cp_pt_line,ST_AsText(ST_ClosestPoint(line,pt)) As cp_line_ptFROM (SELECT 'POINT(100 100)'::geometry As pt,'LINESTRING (20 80, 98 190, 110 180, 50 75 )'::geometry As line) As foo;cp_pt_line | cp_line_pt----------------+------------------------------------------POINT(100 100) | POINT(73.0769230769231 115.384615384615)
ST_ClusterDBSCAN
描述
返回聚类结果ID的窗口函数，基于2维的Density-based spatial clustering of applications with noise (DBSCAN)算法计算聚类的。
函数声明
integer ST_ClusterDBSCAN(geometry winset geom, float8 eps, integer minpoints);
使用示例
ST_ClusterIntersecting
描述
聚合函数。给定一个几何对象的集合，返回由相连组件构成的结果数组。
函数声明
geometry[] ST_ClusterIntersecting(geometry set g);
使用示例
WITH testdata AS(SELECT unnest(ARRAY['LINESTRING (0 0, 1 1)'::geometry,'LINESTRING (5 5, 4 4)'::geometry,'LINESTRING (6 6, 7 7)'::geometry,'LINESTRING (0 0, -1 -1)'::geometry,'POLYGON ((0 0, 4 0, 4 4, 0 4, 0 0))'::geometry]) AS geom)SELECT ST_AsText(unnest(ST_ClusterIntersecting(geom))) FROM testdata;st_astext---------GEOMETRYCOLLECTION(LINESTRING(0 0,1 1),LINESTRING(5 5,4 4),LINESTRING(0 0,-1 -1),POLYGON((0 0,4 0,4 4,0 4,0 0)))GEOMETRYCOLLECTION(LINESTRING(6 6,7 7))
ST_ClusterKMeans
描述
返回每个几何对象所在的聚类结果的ID的窗口函数，聚类由K均值算法生成。
函数声明
integer ST_ClusterKMeans(geometry winset geom, integer number_of_clusters);
使用示例
CREATE TABLE parcels ASSELECT lpad((row_number() over())::text,3,'0') As parcel_id, geom,('{residential, commercial}'::text[])[1 + mod(row_number()OVER(),2)] As typeFROMST_Subdivide(ST_Buffer('LINESTRING(40 100, 98 100, 100 150, 60 90)'::geometry,40, 'endcap=square'),12) As geom;
ST_ClusterWithin
描述
聚合函数。给定一个几何对象的集合，返回由距离不大于给定数值的几何对象构成的GeometryCollections组成的结果数组。
函数声明
geometry[] ST_ClusterWithin(geometry set g, float8 distance);
使用示例
WITH testdata AS(SELECT unnest(ARRAY['LINESTRING (0 0, 1 1)'::geometry,'LINESTRING (5 5, 4 4)'::geometry,'LINESTRING (6 6, 7 7)'::geometry,'LINESTRING (0 0, -1 -1)'::geometry,'POLYGON ((0 0, 4 0, 4 4, 0 4, 0 0))'::geometry]) AS geom)SELECT ST_AsText(unnest(ST_ClusterWithin(geom, 1.4))) FROM testdata;st_astext---------GEOMETRYCOLLECTION(LINESTRING(0 0,1 1),LINESTRING(5 5,4 4),LINESTRING(0 0,-1 -1),POLYGON((0 0,4 0,4 4,0 4,0 0)))GEOMETRYCOLLECTION(LINESTRING(6 6,7 7))
ST_Contains
描述
如果几何对象A包含几何对象B，则返回true。
函数声明
boolean ST_Contains(geometry geomA, geometry geomB);
使用示例
-- A circle within a circleSELECT ST_Contains(smallc, bigc) As smallcontainsbig,ST_Contains(bigc,smallc) As bigcontainssmall,ST_Contains(bigc, ST_Union(smallc, bigc)) as bigcontainsunion,ST_Equals(bigc, ST_Union(smallc, bigc)) as bigisunion,ST_Covers(bigc, ST_ExteriorRing(bigc)) As bigcoversexterior,ST_Contains(bigc, ST_ExteriorRing(bigc)) As bigcontainsexteriorFROM (SELECT ST_Buffer(ST_GeomFromText('POINT(1 2)'), 10) As smallc,ST_Buffer(ST_GeomFromText('POINT(1 2)'), 20) As bigc) As foo;smallcontainsbig | bigcontainssmall | bigcontainsunion | bigisunion | bigcoversexterior | bigcontainsexterior------------------+------------------+------------------+------------+-------------------+---------------------f | t | t | t | t | f-- Example demonstrating difference between contains and contains properlySELECT ST_GeometryType(geomA) As geomtype, ST_Contains(geomA,geomA) AS acontainsa, ST_ContainsProperly(geomA, geomA) AS acontainspropa,ST_Contains(geomA, ST_Boundary(geomA)) As acontainsba, ST_ContainsProperly(geomA, ST_Boundary(geomA)) As acontainspropbaFROM (VALUES ( ST_Buffer(ST_Point(1,1), 5,1) ),( ST_MakeLine(ST_Point(1,1), ST_Point(-1,-1) ) ),( ST_Point(1,1) )) As foo(geomA);geomtype | acontainsa | acontainspropa | acontainsba | acontainspropba--------------+------------+----------------+-------------+-----------------ST_Polygon | t | f | f | fST_LineString | t | f | f | fST_Point | t | t | f | f
ST_ContainsProperly
描述
如果几何对象B完全在几何对象A的内部，则返回true。
函数声明
boolean ST_ContainsProperly(geometry geomA, geometry geomB);
使用示例
--a circle within a circleSELECT ST_ContainsProperly(smallc, bigc) As smallcontainspropbig,ST_ContainsProperly(bigc,smallc) As bigcontainspropsmall,ST_ContainsProperly(bigc, ST_Union(smallc, bigc)) as bigcontainspropunion,ST_Equals(bigc, ST_Union(smallc, bigc)) as bigisunion,ST_Covers(bigc, ST_ExteriorRing(bigc)) As bigcoversexterior,ST_ContainsProperly(bigc, ST_ExteriorRing(bigc)) As bigcontainsexteriorFROM (SELECT ST_Buffer(ST_GeomFromText('POINT(1 2)'), 10) As smallc,ST_Buffer(ST_GeomFromText('POINT(1 2)'), 20) As bigc) As foo;smallcontainspropbig | bigcontainspropsmall | bigcontainspropunion | bigisunion | bigcoversexterior | bigcontainsexterior------------------+------------------+------------------+------------+-------------------+---------------------f | t | f | t | t | f--example demonstrating difference between contains and contains properlySELECT ST_GeometryType(geomA) As geomtype, ST_Contains(geomA,geomA) AS acontainsa, ST_ContainsProperly(geomA, geomA) AS acontainspropa,ST_Contains(geomA, ST_Boundary(geomA)) As acontainsba, ST_ContainsProperly(geomA, ST_Boundary(geomA)) As acontainspropbaFROM (VALUES ( ST_Buffer(ST_Point(1,1), 5,1) ),( ST_MakeLine(ST_Point(1,1), ST_Point(-1,-1) ) ),( ST_Point(1,1) )) As foo(geomA);geomtype | acontainsa | acontainspropa | acontainsba | acontainspropba--------------+------------+----------------+-------------+-----------------ST_Polygon | t | f | f | fST_LineString | t | f | f | fST_Point | t | t | f | f
ST_Covers
描述
如果几何对象或地理对象B没有任何坐标点在几何对象或地理对象A之外，则返回1（TRUE）。
函数声明
boolean ST_Covers(geometry geomA, geometry geomB);boolean ST_Covers(geography geogpolyA, geography geogpointB);
使用示例
--a circle covering a circleSELECT ST_Covers(smallc,smallc) As smallinsmall,ST_Covers(smallc, bigc) As smallcoversbig,ST_Covers(bigc, ST_ExteriorRing(bigc)) As bigcoversexterior,ST_Contains(bigc, ST_ExteriorRing(bigc)) As bigcontainsexteriorFROM (SELECT ST_Buffer(ST_GeomFromText('POINT(1 2)'), 10) As smallc,ST_Buffer(ST_GeomFromText('POINT(1 2)'), 20) As bigc) As foo;smallinsmall | smallcoversbig | bigcoversexterior | bigcontainsexterior--------------+----------------+-------------------+---------------------t | f | t | f(1 row)
ST_CoveredBy
描述
如果几何对象或地理对象A没有任何坐标点在几何对象或地理对象B之外，则返回1（TRUE）。
函数声明
boolean ST_CoveredBy(geometry geomA, geometry geomB);boolean ST_CoveredBy(geography geogA, geography geogB);
使用示例
--a circle coveredby a circleSELECT ST_CoveredBy(smallc,smallc) As smallinsmall,ST_CoveredBy(smallc, bigc) As smallcoveredbybig,ST_CoveredBy(ST_ExteriorRing(bigc), bigc) As exteriorcoveredbybig,ST_Within(ST_ExteriorRing(bigc),bigc) As exeriorwithinbigFROM (SELECT ST_Buffer(ST_GeomFromText('POINT(1 2)'), 10) As smallc,ST_Buffer(ST_GeomFromText('POINT(1 2)'), 20) As bigc) As foo;smallinsmall | smallcoveredbybig | exteriorcoveredbybig | exeriorwithinbig--------------+-------------------+----------------------+------------------t | t | t | f(1 row)
ST_Crosses
描述
如果给定的两个几何对象相交，则返回true。
函数声明
boolean ST_Crosses(geometry g1, geometry g2);
使用示例
CREATE TABLE roads (id serial NOT NULL,the_geom geometry,CONSTRAINT roads_pkey PRIMARY KEY (road_id));
ST_LineCrossingDirection
描述
给定两个LineString，返回一个-3到3之间的整数，代表不同的相关的方式：
- 0: LINE NO CROSS
- -1: LINE CROSS LEFT
- 1: LINE CROSS RIGHT
- -2: LINE MULTICROSS END LEFT
- 2: LINE MULTICROSS END RIGHT
- -3: LINE MULTICROSS END SAME FIRST LEFT
- 3: LINE MULTICROSS END SAME FIRST RIGHT
函数声明
integer ST_LineCrossingDirection(geometry linestringA, geometry linestringB);
使用示例
SELECT ST_LineCrossingDirection(foo.line1, foo.line2) As l1_cross_l2 ,ST_LineCrossingDirection(foo.line2, foo.line1) As l2_cross_l1FROM (SELECTST_GeomFromText('LINESTRING(25 169,89 114,40 70,86 43)') As line1,ST_GeomFromText('LINESTRING(171 154,20 140,71 74,161 53)') As line2) As foo;l1_cross_l2 | l2_cross_l1-------------+-------------3 | -3
ST_Disjoint
描述
如果给定的两个几何对象不相接，返回TRUE。
函数声明
boolean ST_Disjoint(geometry A, geometry B);
使用示例
SELECT ST_Disjoint('POINT(0 0)'::geometry, 'LINESTRING ( 2 0, 0 2 )'::geometry);st_disjoint---------------t(1 row)SELECT ST_Disjoint('POINT(0 0)'::geometry, 'LINESTRING ( 0 0, 0 2 )'::geometry);st_disjoint---------------f(1 row)
ST_Distance
描述
对于几何对象，返回2维基于参考坐标系的笛卡尔距离。对于地理对象，返回两个对象的最小球面距离，以米为单位。
函数声明
float ST_Distance(geometry g1, geometry g2);float ST_Distance(geography gg1, geography gg2);float ST_Distance(geography gg1, geography gg2, boolean use_spheroid);
使用示例
--Geometry example - units in planar degrees 4326 is WGS 84 long lat unit=degreesSELECT ST_Distance('SRID=4326;POINT(-72.1235 42.3521)'::geometry,'SRID=4326;LINESTRING(-72.1260 42.45, -72.123 42.1546)'::geometry);st_distance-----------------0.00150567726382282-- Geometry example - units in meters (SRID: 3857, proportional to pixels on popular web maps)-- although the value is off, nearby ones can be compared correctly,-- which makes it a good choice for algorithms like KNN or KMeans.SELECT ST_Distance(ST_Transform('SRID=4326;POINT(-72.1235 42.3521)'::geometry, 3857),ST_Transform('SRID=4326;LINESTRING(-72.1260 42.45, -72.123 42.1546)'::geometry, 3857));st_distance-----------------167.441410065196-- Geometry example - units in meters (SRID: 3857 as above, but corrected by cos(lat) to account for distortion)SELECT ST_Distance(ST_Transform('SRID=4326;POINT(-72.1235 42.3521)'::geometry, 3857),ST_Transform('SRID=4326;LINESTRING(-72.1260 42.45, -72.123 42.1546)'::geometry, 3857)) * cosd(42.3521);st_distance-----------------123.742351254151-- Geometry example - units in meters (SRID: 26986 Massachusetts state plane meters) (most accurate for Massachusetts)SELECT ST_Distance(ST_Transform('SRID=4326;POINT(-72.1235 42.3521)'::geometry, 26986),ST_Transform('SRID=4326;LINESTRING(-72.1260 42.45, -72.123 42.1546)'::geometry, 26986));st_distance-----------------123.797937878454-- Geometry example - units in meters (SRID: 2163 US National Atlas Equal area) (least accurate)SELECT ST_Distance(ST_Transform('SRID=4326;POINT(-72.1235 42.3521)'::geometry, 2163),ST_Transform('SRID=4326;LINESTRING(-72.1260 42.45, -72.123 42.1546)'::geometry, 2163));st_distance------------------126.664256056812
ST_MinimumClearance
描述
返回给定几何对象的最小间隙。
函数声明
float ST_MinimumClearance(geometry g);
使用示例
SELECT ST_MinimumClearance('POLYGON ((0 0, 1 0, 1 1, 0.5 3.2e-4, 0 0))');st_minimumclearance---------------------0.00032
ST_MinimumClearanceLine
描述
返回一个包含两个点的LineString，代表了给定几何对象的最小间隙。
函数声明
Geometry ST_MinimumClearanceLine(geometry g);
使用示例
SELECT ST_AsText(ST_MinimumClearanceLine('POLYGON ((0 0, 1 0, 1 1, 0.5 3.2e-4, 0 0))'));st_astext-------------------------------LINESTRING(0.5 0.00032,0.5 0)
ST_HausdorffDistance
描述
返回给定的两个几何对象的豪斯多夫距离。
函数声明
float ST_HausdorffDistance(geometry g1, geometry g2);float ST_HausdorffDistance(geometry g1, geometry g2, float densifyFrac);
使用示例
SELECT DISTINCT ON(buildings.gid) buildings.gid, parcels.parcel_idFROM buildings INNER JOIN parcels ON ST_Intersects(buildings.geom,parcels.geom)ORDER BY buildings.gid, ST_HausdorffDistance(buildings.geom, parcels.geom);
ST_FrechetDistance
描述
返回给定的两个几何对象的弗雷歇距离。
函数声明
float ST_FrechetDistance(geometry g1, geometry g2, float densifyFrac = -1);
使用示例
SELECT st_frechetdistance('LINESTRING (0 0, 100 0)'::geometry, 'LINESTRING (0 0, 50 50, 100 0)'::geometry);st_frechetdistance--------------------70.7106781186548(1 row)
ST_MaxDistance
描述
返回两个给定的几何对象之间的最远距离。
函数声明
float ST_MaxDistance(geometry g1, geometry g2);
使用示例
SELECT ST_MaxDistance('POINT(0 0)'::geometry, 'LINESTRING ( 2 0, 0 2 )'::geometry);st_maxdistance-----------------2(1 row)SELECT ST_MaxDistance('POINT(0 0)'::geometry, 'LINESTRING ( 2 2, 2 2 )'::geometry);st_maxdistance------------------2.82842712474619(1 row)
ST_DistanceSphere
描述
返回给定经纬度几何对象的球面距离。比ST_DistanceSpheroid更快。
函数声明
float ST_DistanceSphere(geometry geomlonlatA, geometry geomlonlatB);
使用示例
SELECT round(CAST(ST_DistanceSphere(ST_Centroid(the_geom), ST_GeomFromText('POINT(-118 38)',4326)) As numeric),2) As dist_meters,round(CAST(ST_Distance(ST_Transform(ST_Centroid(the_geom),32611),ST_Transform(ST_GeomFromText('POINT(-118 38)', 4326),32611)) As numeric),2) As dist_utm11_meters,round(CAST(ST_Distance(ST_Centroid(the_geom), ST_GeomFromText('POINT(-118 38)', 4326)) As numeric),5) As dist_degrees,round(CAST(ST_Distance(ST_Transform(the_geom,32611),ST_Transform(ST_GeomFromText('POINT(-118 38)', 4326),32611)) As numeric),2) As min_dist_line_point_metersFROM(SELECT ST_GeomFromText('LINESTRING(-118.584 38.374,-118.583 38.5)', 4326) As the_geom) as foo;dist_meters | dist_utm11_meters | dist_degrees | min_dist_line_point_meters-------------+-------------------+--------------+----------------------------70424.47 | 70438.00 | 0.72900 | 65871.18
ST_DistanceSpheroid
描述
返回给定经纬度几何对象的球体距离。比ST_DistanceSpheroid更快。
函数声明
float ST_DistanceSpheroid(geometry geomlonlatA, geometry geomlonlatB, spheroid measurement_spheroid);
使用示例
SELECT round(CAST(ST_DistanceSpheroid(ST_Centroid(the_geom), ST_GeomFromText('POINT(-118 38)',4326), 'SPHEROID["WGS 84",6378137,298.257223563]')As numeric),2) As dist_meters_spheroid,round(CAST(ST_DistanceSphere(ST_Centroid(the_geom), ST_GeomFromText('POINT(-118 38)',4326)) As numeric),2) As dist_meters_sphere,round(CAST(ST_Distance(ST_Transform(ST_Centroid(the_geom),32611),ST_Transform(ST_GeomFromText('POINT(-118 38)', 4326),32611)) As numeric),2) As dist_utm11_metersFROM(SELECT ST_GeomFromText('LINESTRING(-118.584 38.374,-118.583 38.5)', 4326) As the_geom) as foo;dist_meters_spheroid | dist_meters_sphere | dist_utm11_meters----------------------+--------------------+-------------------70454.92 | 70424.47 | 70438.00
ST_DFullyWithin
描述
如果给定的几何对象互相之间的距离都小于给定的数值，则返回true。
函数声明
boolean ST_DFullyWithin(geometry g1, geometry g2, double precision distance);
使用示例
SELECT ST_DFullyWithin(geom_a, geom_b, 10) as DFullyWithin10, ST_DWithin(geom_a, geom_b, 10) as DWithin10, ST_DFullyWithin(geom_a, geom_b, 20) as DFullyWithin20 from(select ST_GeomFromText('POINT(1 1)') as geom_a,ST_GeomFromText('LINESTRING(1 5, 2 7, 1 9, 14 12)') as geom_b) t1;-----------------DFullyWithin10 | DWithin10 | DFullyWithin20 |---------------+----------+---------------+f | t | t |
ST_DWithin
描述
如果给定的几何对象互相之间的距离都在给定的数值之内，则返回true。
函数声明
boolean ST_DWithin(geometry g1, geometry g2, double precision distance_of_srid);boolean ST_DWithin(geography gg1, geography gg2, double precision distance_meters);boolean ST_DWithin(geography gg1, geography gg2, double precision distance_meters, boolean use_spheroid);
使用示例
-- Find the nearest hospital to each school-- that is within 3000 units of the school.-- We do an ST_DWithin search to utilize indexes to limit our search list-- that the non-indexable ST_Distance needs to process-- If the units of the spatial reference is meters then units would be metersSELECT DISTINCT ON (s.gid) s.gid, s.school_name, s.geom, h.hospital_nameFROM schools sLEFT JOIN hospitals h ON ST_DWithin(s.the_geom, h.geom, 3000)ORDER BY s.gid, ST_Distance(s.geom, h.geom);-- The schools with no close hospitals-- Find all schools with no hospital within 3000 units-- away from the school. Units is in units of spatial ref (e.g. meters, feet, degrees)SELECT s.gid, s.school_nameFROM schools sLEFT JOIN hospitals h ON ST_DWithin(s.geom, h.geom, 3000)WHERE h.gid IS NULL;-- Find broadcasting towers that receiver with limited range can receive.-- Data is geometry in Spherical Mercator (SRID=3857), ranges are approximate.-- Create geometry index that will check proximity limit of user to towerCREATE INDEX ON broadcasting_towers using gist (geom);-- Create geometry index that will check proximity limit of tower to userCREATE INDEX ON broadcasting_towers using gist (ST_Expand(geom, sending_range));-- Query towers that 4-kilometer receiver in Minsk Hackerspace can get-- Note: two conditions, because shorter LEAST(b.sending_range, 4000) will not use index.SELECT b.tower_id, b.geomFROM broadcasting_towers bWHERE ST_DWithin(b.geom, 'SRID=3857;POINT(3072163.4 7159374.1)', 4000)AND ST_DWithin(b.geom, 'SRID=3857;POINT(3072163.4 7159374.1)', b.sending_range);
ST_Equals
描述
如果给定的两个几何对象代表了同一个对象，那么返回true。
函数声明
boolean ST_Equals(geometry A, geometry B);
使用示例
SELECT ST_Equals(ST_GeomFromText('LINESTRING(0 0, 10 10)'),ST_GeomFromText('LINESTRING(0 0, 5 5, 10 10)'));st_equals-----------t(1 row)SELECT ST_Equals(ST_Reverse(ST_GeomFromText('LINESTRING(0 0, 10 10)')),ST_GeomFromText('LINESTRING(0 0, 5 5, 10 10)'));st_equals-----------t(1 row)
ST_GeometricMedian
描述
返回给定几何对象的几何中位点。
函数声明
geometry ST_GeometricMedian ( geometry g , float8 tolerance , int max_iter , boolean fail_if_not_converged );
使用示例
WITH test AS (SELECT 'MULTIPOINT((0 0), (1 1), (2 2), (200 200))'::geometry geom)SELECTST_AsText(ST_Centroid(geom)) centroid,ST_AsText(ST_GeometricMedian(geom)) medianFROM test;centroid | median--------------------+----------------------------------------POINT(50.75 50.75) | POINT(1.9761550281255 1.9761550281255)(1 row)
ST_HasArc
描述
如果给定几何对象或几何对象的集合包含有环，则返回true。
函数声明
boolean ST_HasArc(geometry geomA);
使用示例
SELECT ST_HasArc(ST_Collect('LINESTRING(1 2, 3 4, 5 6)', 'CIRCULARSTRING(1 1, 2 3, 4 5, 6 7, 5 6)'));st_hasarc--------t
ST_Intersects
描述
如果给定的几何对象在2维空间内相交，则返回true。如果两个坐标点距离小于0.00001米，则视为相交。
函数声明
boolean ST_Intersects( geometry geomA , geometry geomB );boolean ST_Intersects( geography geogA , geography geogB );
使用示例
SELECT ST_Intersects('POINT(0 0)'::geometry, 'LINESTRING ( 2 0, 0 2 )'::geometry);st_intersects---------------f(1 row)SELECT ST_Intersects('POINT(0 0)'::geometry, 'LINESTRING ( 0 0, 0 2 )'::geometry);st_intersects---------------t(1 row)
ST_Length
描述
对于给定的LineString或MultiLineString，返回其2维空间内的长度。
函数声明
float ST_Length(geometry a_2dlinestring);float ST_Length(geography geog, boolean use_spheroid=true);
使用示例
SELECT ST_Length(ST_GeomFromText('LINESTRING(743238 2967416,743238 2967450,743265 2967450,743265.625 2967416,743238 2967416)',2249));st_length---------122.630744000095--Transforming WGS 84 LineString to Massachusetts state plane metersSELECT ST_Length(ST_Transform(ST_GeomFromEWKT('SRID=4326;LINESTRING(-72.1260 42.45, -72.1240 42.45666, -72.123 42.1546)'),26986));st_length---------34309.4563576191
ST_Length2D
描述
对于给定的LineString或MultiLineString，返回其2维空间内的长度。与ST_Length相同。
函数声明
float ST_Length2D(geometry a_2dlinestring);
使用示例
None
ST_3DLength
描述
对于给定的LineString或MultiLineString，返回其3维空间内的长度。
函数声明
float ST_3DLength(geometry a_3dlinestring);
使用示例
SELECT ST_3DLength(ST_GeomFromText('LINESTRING(743238 2967416 1,743238 2967450 1,743265 2967450 3,743265.625 2967416 3,743238 2967416 3)',2249));ST_3DLength-----------122.704716741457
ST_LengthSpheroid
描述
计算给定几何对象的2维或3维椭球长度。
函数声明
float ST_LengthSpheroid(geometry a_geometry, spheroid a_spheroid);
使用示例
SELECT ST_LengthSpheroid( geometry_column,'SPHEROID["GRS_1980",6378137,298.257222101]' )FROM geometry_table;SELECT ST_LengthSpheroid( the_geom, sph_m ) As tot_len,ST_LengthSpheroid(ST_GeometryN(the_geom,1), sph_m) As len_line1,ST_LengthSpheroid(ST_GeometryN(the_geom,2), sph_m) As len_line2FROM (SELECT ST_GeomFromText('MULTILINESTRING((-118.584 38.374,-118.583 38.5),(-71.05957 42.3589 , -71.061 43))') As the_geom,CAST('SPHEROID["GRS_1980",6378137,298.257222101]' As spheroid) As sph_m) as foo;tot_len | len_line1 | len_line2------------------+------------------+------------------85204.5207562955 | 13986.8725229309 | 71217.6482333646--3DSELECT ST_LengthSpheroid( the_geom, sph_m ) As tot_len,ST_LengthSpheroid(ST_GeometryN(the_geom,1), sph_m) As len_line1,ST_LengthSpheroid(ST_GeometryN(the_geom,2), sph_m) As len_line2FROM (SELECT ST_GeomFromEWKT('MULTILINESTRING((-118.584 38.374 20,-118.583 38.5 30),(-71.05957 42.3589 75, -71.061 43 90))') As the_geom,CAST('SPHEROID["GRS_1980",6378137,298.257222101]' As spheroid) As sph_m) as foo;tot_len | len_line1 | len_line2------------------+-----------------+------------------85204.5259107402 | 13986.876097711 | 71217.6498130292
ST_Length2D_Spheroid
描述
计算给定几何对象的2维椭球长度。
函数声明
float ST_Length2D_Spheroid(geometry a_geometry, spheroid a_spheroid);
使用示例
SELECT ST_Length2D_Spheroid( geometry_column,'SPHEROID["GRS_1980",6378137,298.257222101]' )FROM geometry_table;SELECT ST_Length2D_Spheroid( the_geom, sph_m ) As tot_len,ST_Length2D_Spheroid(ST_GeometryN(the_geom,1), sph_m) As len_line1,ST_Length2D_Spheroid(ST_GeometryN(the_geom,2), sph_m) As len_line2FROM (SELECT ST_GeomFromText('MULTILINESTRING((-118.584 38.374,-118.583 38.5),(-71.05957 42.3589 , -71.061 43))') As the_geom,CAST('SPHEROID["GRS_1980",6378137,298.257222101]' As spheroid) As sph_m) as foo;tot_len | len_line1 | len_line2------------------+------------------+------------------85204.5207562955 | 13986.8725229309 | 71217.6482333646--3D Observe same answerSELECT ST_Length2D_Spheroid( the_geom, sph_m ) As tot_len,ST_Length2D_Spheroid(ST_GeometryN(the_geom,1), sph_m) As len_line1,ST_Length2D_Spheroid(ST_GeometryN(the_geom,2), sph_m) As len_line2FROM (SELECT ST_GeomFromEWKT('MULTILINESTRING((-118.584 38.374 20,-118.583 38.5 30),(-71.05957 42.3589 75, -71.061 43 90))') As the_geom,CAST('SPHEROID["GRS_1980",6378137,298.257222101]' As spheroid) As sph_m) as foo;tot_len | len_line1 | len_line2------------------+------------------+------------------85204.5207562955 | 13986.8725229309 | 71217.6482333646
ST_LongestLine
描述
返回给定的两个2维几何对象的最远距离的线段。
函数声明
geometry ST_LongestLine(geometry g1, geometry g2);
使用示例
SELECT ST_AsText(ST_LongestLine('POINT(100 100)'::geometry,'LINESTRING (20 80, 98 190, 110 180, 50 75 )'::geometry)) As lline;lline-----------------LINESTRING(100 100,98 190)
ST_OrderingEquals
描述
如果两个几何对象相同，而且坐标点的顺序也相同，返回true。
函数声明
boolean ST_OrderingEquals(geometry A, geometry B);
使用示例
SELECT ST_OrderingEquals(ST_GeomFromText('LINESTRING(0 0, 10 10)'),ST_GeomFromText('LINESTRING(0 0, 5 5, 10 10)'));st_orderingequals-----------f(1 row)SELECT ST_OrderingEquals(ST_GeomFromText('LINESTRING(0 0, 10 10)'),ST_GeomFromText('LINESTRING(0 0, 0 0, 10 10)'));st_orderingequals-----------t(1 row)SELECT ST_OrderingEquals(ST_Reverse(ST_GeomFromText('LINESTRING(0 0, 10 10)')),ST_GeomFromText('LINESTRING(0 0, 0 0, 10 10)'));st_orderingequals-----------f(1 row)
ST_Overlaps
描述
如果两个几何对象相交，返回TRUE。
函数声明
boolean ST_Overlaps(geometry A, geometry B);
使用示例
--a point on a line is contained by the line and is of a lower dimension, and therefore does not overlap the linenor crossesSELECT ST_Overlaps(a,b) As a_overlap_b,ST_Crosses(a,b) As a_crosses_b,ST_Intersects(a, b) As a_intersects_b, ST_Contains(b,a) As b_contains_aFROM (SELECT ST_GeomFromText('POINT(1 0.5)') As a, ST_GeomFromText('LINESTRING(1 0, 1 1, 3 5)') As b)As foo;a_overlap_b | a_crosses_b | a_intersects_b | b_contains_a------------+-------------+----------------+--------------f | f | t | t--a line that is partly contained by circle, but not fully is defined as intersecting and crossing,-- but since of different dimension it does not overlapSELECT ST_Overlaps(a,b) As a_overlap_b, ST_Crosses(a,b) As a_crosses_b,ST_Intersects(a, b) As a_intersects_b,ST_Contains(a,b) As a_contains_bFROM (SELECT ST_Buffer(ST_GeomFromText('POINT(1 0.5)'), 3) As a, ST_GeomFromText('LINESTRING(1 0, 1 1, 3 5)') As b)As foo;a_overlap_b | a_crosses_b | a_intersects_b | a_contains_b-------------+-------------+----------------+--------------f | t | t | f-- a 2-dimensional bent hot dog (aka buffered line string) that intersects a circle,-- but is not fully contained by the circle is defined as overlapping since they are of the same dimension,-- but it does not cross, because the intersection of the 2 is of the same dimension-- as the maximum dimension of the 2SELECT ST_Overlaps(a,b) As a_overlap_b, ST_Crosses(a,b) As a_crosses_b, ST_Intersects(a, b) As a_intersects_b,ST_Contains(b,a) As b_contains_a,ST_Dimension(a) As dim_a, ST_Dimension(b) as dim_b, ST_Dimension(ST_Intersection(a,b)) As dima_intersection_bFROM (SELECT ST_Buffer(ST_GeomFromText('POINT(1 0.5)'), 3) As a,ST_Buffer(ST_GeomFromText('LINESTRING(1 0, 1 1, 3 5)'),0.5) As b)As foo;a_overlap_b | a_crosses_b | a_intersects_b | b_contains_a | dim_a | dim_b | dima_intersection_b-------------+-------------+----------------+--------------+-------+-------+---------------------t | f | t | f | 2 | 2 | 2
ST_Perimeter
描述
返回给定几何对象或地理对象的周长。
函数声明
float ST_Perimeter(geometry g1);float ST_Perimeter(geography geog, boolean use_spheroid=true);
使用示例
SELECT ST_Perimeter(ST_GeomFromText('POLYGON((743238 2967416,743238 2967450,743265 2967450,743265.625 2967416,743238 2967416))', 2249));st_perimeter---------122.630744000095(1 row)SELECT ST_Perimeter(ST_GeomFromText('MULTIPOLYGON(((763104.471273676 2949418.44119003,763104.477769673 2949418.42538203,763104.189609677 2949418.22343004,763104.471273676 2949418.44119003)),((763104.471273676 2949418.44119003,763095.804579742 2949436.33850239,763086.132105649 2949451.46730207,763078.452329651 2949462.11549407,763075.354136904 2949466.17407812,763064.362142565 2949477.64291974,763059.953961626 2949481.28983009,762994.637609571 2949532.04103014,762990.568508415 2949535.06640477,762986.710889563 2949539.61421415,763117.237897679 2949709.50493431,763235.236617789 2949617.95619822,763287.718121842 2949562.20592617,763111.553321674 2949423.91664605,763104.471273676 2949418.44119003)))', 2249));st_perimeter---------845.227713366825(1 row)
ST_Perimeter2D
描述
返回给定几何对象的2维周长。目前与ST_Perimeter相同。
函数声明
float ST_Perimeter2D(geometry geomA);
使用示例
None
ST_3DPerimeter
描述
返回给定几何对象的3维周长。
函数声明
float ST_3DPerimeter(geometry geomA);
使用示例
SELECT ST_3DPerimeter(the_geom), ST_Perimeter2d(the_geom), ST_Perimeter(the_geom) FROM(SELECT ST_GeomFromEWKT('SRID=2249;POLYGON((743238 2967416 2,743238 2967450 1,743265.625 2967416 1,743238 2967416 2))') As the_geom) As foo;ST_3DPerimeter | st_perimeter2d | st_perimeter------------------+------------------+------------------105.465793597674 | 105.432997272188 | 105.432997272188
ST_PointOnSurface
描述
返回与给定几何对象的表面相交的一个坐标点。
函数声明
geometry ST_PointOnSurface(geometry g1);
使用示例
SELECT ST_AsText(ST_PointOnSurface('POINT(0 5)'::geometry));st_astext------------POINT(0 5)(1 row)SELECT ST_AsText(ST_PointOnSurface('LINESTRING(0 5, 0 10)'::geometry));st_astext------------POINT(0 5)(1 row)SELECT ST_AsText(ST_PointOnSurface('POLYGON((0 0, 0 5, 5 5, 5 0, 0 0))'::geometry));st_astext----------------POINT(2.5 2.5)(1 row)SELECT ST_AsEWKT(ST_PointOnSurface(ST_GeomFromEWKT('LINESTRING(0 5 1, 0 0 1, 0 10 2)')));st_asewkt----------------POINT(0 0 1)(1 row)
ST_Project
描述
将一个地理坐标点按给定的距离（以米为单位）和角度（北方为0度，东方为90度，南方为180度，西方是270度）做投影变换。
函数声明
geography ST_Project(geography g1, float distance, float azimuth);
使用示例
SELECT ST_AsText(ST_Project('POINT(0 0)'::geography, 100000, radians(45.0)));st_astext--------------------------------------------POINT(0.635231029125537 0.639472334729198)(1 row)
ST_Relate
描述
如果给定的几何对象与另一个给定的几何对象相关，则返回true。
函数声明
boolean ST_Relate(geometry geomA, geometry geomB, text intersectionMatrixPattern);text ST_Relate(geometry geomA, geometry geomB);text ST_Relate(geometry geomA, geometry geomB, integer BoundaryNodeRule);
使用示例
--Find all compounds that intersect and not touch a poly (interior intersects)SELECT l.* , b.name As poly_nameFROM polys As bINNER JOIN compounds As lON (p.the_geom && b.the_geomAND ST_Relate(l.the_geom, b.the_geom,'T********'));SELECT ST_Relate(ST_GeometryFromText('POINT(1 2)'), ST_Buffer(ST_GeometryFromText('POINT(1 2)'),2));st_relate-----------0FFFFF212SELECT ST_Relate(ST_GeometryFromText('LINESTRING(1 2, 3 4)'), ST_GeometryFromText('LINESTRING(5 6, 7 8)'));st_relate-----------FF1FF0102SELECT ST_Relate(ST_GeometryFromText('POINT(1 2)'), ST_Buffer(ST_GeometryFromText('POINT(1 2)'),2), '0FFFFF212');st_relate-----------tSELECT ST_Relate(ST_GeometryFromText('POINT(1 2)'), ST_Buffer(ST_GeometryFromText('POINT(1 2)'),2), '*FF*FF212');st_relate-----------t
ST_RelateMatch
描述
返回给定的相交矩阵是否满足给定的相交模式。
函数声明
boolean ST_RelateMatch(text intersectionMatrix, text intersectionMatrixPattern);
使用示例
SELECT ST_RelateMatch('101202FFF', 'TTTTTTFFF') ;-- result --t--example of common intersection matrix patterns and example matrices-- comparing relationships of involving one invalid geometry and ( a line and polygon that intersect at interior and boundary)SELECT mat.name, pat.name, ST_RelateMatch(mat.val, pat.val) As satisfiedFROM( VALUES ('Equality', 'T1FF1FFF1'),('Overlaps', 'T*T***T**'),('Within', 'T*F**F***'),('Disjoint', 'FF*FF****') As pat(name,val)CROSS JOIN( VALUES ('Self intersections (invalid)', '111111111'),('IE2_BI1_BB0_BE1_EI1_EE2', 'FF2101102'),('IB1_IE1_BB0_BE0_EI2_EI1_EE2', 'F11F00212')) As mat(name,val);
ST_ShortestLine
描述
返回两个几何对象间的2维最短线段。
函数声明
geometry ST_ShortestLine(geometry g1, geometry g2);
使用示例
SELECT ST_AsText(ST_ShortestLine('POINT(100 100)'::geometry,'LINESTRING (20 80, 98 190, 110 180, 50 75 )'::geometry)) As sline;sline-----------------LINESTRING(100 100,73.0769230769231 115.384615384615)
ST_Touches
描述
返回给定的两个几何对象是否相接。
函数声明
boolean ST_Touches(geometry g1, geometry g2);
使用示例
SELECT ST_Touches('LINESTRING(0 0, 1 1, 0 2)'::geometry, 'POINT(1 1)'::geometry);st_touches------------f(1 row)SELECT ST_Touches('LINESTRING(0 0, 1 1, 0 2)'::geometry, 'POINT(0 2)'::geometry);st_touches------------t(1 row)
ST_Within
描述
如果给定的几何对象A完全在几何对象B之内，返回true。
函数声明
boolean ST_Within(geometry A, geometry B);
使用示例
--a circle within a circleSELECT ST_Within(smallc,smallc) As smallinsmall,ST_Within(smallc, bigc) As smallinbig,ST_Within(bigc,smallc) As biginsmall,ST_Within(ST_Union(smallc, bigc), bigc) as unioninbig,ST_Within(bigc, ST_Union(smallc, bigc)) as biginunion,ST_Equals(bigc, ST_Union(smallc, bigc)) as bigisunionFROM(SELECT ST_Buffer(ST_GeomFromText('POINT(50 50)'), 20) As smallc,ST_Buffer(ST_GeomFromText('POINT(50 50)'), 40) As bigc) As foo;--Resultsmallinsmall | smallinbig | biginsmall | unioninbig | biginunion | bigisunion--------------+------------+------------+------------+------------+------------t | t | f | t | t | t(1 row)
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