Geometry AccessorsGeometryTypeReturns the type of the geometry as a string. Eg:
'LINESTRING', 'POLYGON', 'MULTIPOINT', etc.text GeometryTypegeometry geomADescriptionReturns the type of the geometry as a string. Eg:
'LINESTRING', 'POLYGON', 'MULTIPOINT', etc.OGC SPEC s2.1.1.1 - Returns the name of the instantiable
subtype of Geometry of which this Geometry instance is a member.
The name of the instantiable subtype of Geometry is returned as a
string.This function also indicates if the geometry is measured,
by returning a string of the form 'POINTM'.Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.&sfs_compliant;&curve_support;&Z_support;&P_support;&T_support;ExamplesSELECT GeometryType(ST_GeomFromText('LINESTRING(77.29 29.07,77.42 29.26,77.27 29.31,77.29 29.07)'));
geometrytype
--------------
LINESTRING
SELECT ST_GeometryType(ST_GeomFromEWKT('POLYHEDRALSURFACE( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)),
((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)), ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)), ((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)) )'));
--result
POLYHEDRALSURFACE
SELECT GeometryType(geom) as result
FROM
(SELECT
ST_GeomFromEWKT('TIN (((
0 0 0,
0 0 1,
0 1 0,
0 0 0
)), ((
0 0 0,
0 1 0,
1 1 0,
0 0 0
))
)') AS geom
) AS g;
result
--------
TIN See AlsoST_BoundaryReturns the closure of the combinatorial boundary of this
Geometry.geometry ST_Boundarygeometry geomADescriptionReturns the closure of the combinatorial boundary of this
Geometry. The combinatorial boundary is defined as described in
section 3.12.3.2 of the OGC SPEC. Because the result of this
function is a closure, and hence topologically closed, the
resulting boundary can be represented using representational
geometry primitives as discussed in the OGC SPEC, section
3.12.2.Performed by the GEOS modulePrior to 2.0.0, this function throws an exception if used with GEOMETRYCOLLECTION. From 2.0.0 up it will return NULL instead (unsupported input).&sfs_compliant; OGC SPEC s2.1.1.1&sqlmm_compliant; SQL-MM 3: 5.1.14&Z_support;ExamplesSELECT ST_AsText(ST_Boundary(ST_GeomFromText('LINESTRING(1 1,0 0, -1 1)')));
st_astext
-----------
MULTIPOINT(1 1,-1 1)
SELECT ST_AsText(ST_Boundary(ST_GeomFromText('POLYGON((1 1,0 0, -1 1, 1 1))')));
st_astext
----------
LINESTRING(1 1,0 0,-1 1,1 1)
--Using a 3d polygon
SELECT ST_AsEWKT(ST_Boundary(ST_GeomFromEWKT('POLYGON((1 1 1,0 0 1, -1 1 1, 1 1 1))')));
st_asewkt
-----------------------------------
LINESTRING(1 1 1,0 0 1,-1 1 1,1 1 1)
--Using a 3d multilinestring
SELECT ST_AsEWKT(ST_Boundary(ST_GeomFromEWKT('MULTILINESTRING((1 1 1,0 0 0.5, -1 1 1),(1 1 0.5,0 0 0.5, -1 1 0.5, 1 1 0.5) )')));
st_asewkt
----------
MULTIPOINT(-1 1 1,1 1 0.75)
See Also, ST_CoordDimReturn the coordinate dimension of the ST_Geometry value.integer ST_CoordDimgeometry geomADescriptionReturn the coordinate dimension of the ST_Geometry value.This is the MM compliant alias name for &sfs_compliant;&sqlmm_compliant; SQL-MM 3: 5.1.3&curve_support;&Z_support;&P_support;&T_support;ExamplesSELECT ST_CoordDim('CIRCULARSTRING(1 2 3, 1 3 4, 5 6 7, 8 9 10, 11 12 13)');
---result--
3
SELECT ST_CoordDim(ST_Point(1,2));
--result--
2
See AlsoST_DimensionThe inherent dimension of this Geometry object, which must
be less than or equal to the coordinate dimension. integer ST_Dimensiongeometry gDescriptionThe inherent dimension of this Geometry object, which must
be less than or equal to the coordinate dimension. OGC SPEC
s2.1.1.1 - returns 0 for POINT, 1 for LINESTRING, 2 for POLYGON, and
the largest dimension of the components of a
GEOMETRYCOLLECTION.
If unknown (empty geometry) null is returned.
&sqlmm_compliant; SQL-MM 3: 5.1.2Enhanced: 2.0.0 support for Polyhedral surfaces and TINs was introduced. No longer throws an exception if given empty geometry.Prior to 2.0.0, this function throws an exception if used with empty geometry. &P_support;&T_support;ExamplesSELECT ST_Dimension('GEOMETRYCOLLECTION(LINESTRING(1 1,0 0),POINT(0 0))');
ST_Dimension
-----------
1
See AlsoST_EndPointReturns the last point of a LINESTRING
geometry as a POINT.boolean ST_EndPointgeometry gDescriptionReturns the last point of a LINESTRING geometry
as a POINT or NULL if the input
parameter is not a LINESTRING.&sqlmm_compliant; SQL-MM 3: 7.1.4&Z_support;Changed: 2.0.0 no longer works with single geometry multilinestrings. In older
versions of PostGIS -- a single line multilinestring would work happily with this
function and return the start point. In 2.0.0 it just returns NULL like any other multilinestring.
The older behavior was an undocumented feature, but people who assumed they had their data stored as LINESTRING
may experience these returning NULL in 2.0 now.Examplespostgis=# SELECT ST_AsText(ST_EndPoint('LINESTRING(1 1, 2 2, 3 3)'::geometry));
st_astext
------------
POINT(3 3)
(1 row)
postgis=# SELECT ST_EndPoint('POINT(1 1)'::geometry) IS NULL AS is_null;
is_null
----------
t
(1 row)
--3d endpoint
SELECT ST_AsEWKT(ST_EndPoint('LINESTRING(1 1 2, 1 2 3, 0 0 5)'));
st_asewkt
--------------
POINT(0 0 5)
(1 row)
See Also, ST_EnvelopeReturns a geometry representing the double precision (float8) bounding box of the
supplied geometry.geometry ST_Envelopegeometry g1DescriptionReturns the float8 minimum bounding box for the supplied geometry, as a geometry.
The polygon is defined by the corner points of the bounding box
((MINX, MINY),
(MINX, MAXY),
(MAXX, MAXY),
(MAXX, MINY),
(MINX, MINY)). (PostGIS will add a
ZMIN/ZMAX coordinate as
well).Degenerate cases (vertical lines, points) will return a geometry of
lower dimension than POLYGON, ie.
POINT or LINESTRING.Availability: 1.5.0 behavior changed to output double precision instead of float4&sfs_compliant; s2.1.1.1&sqlmm_compliant; SQL-MM 3: 5.1.15Examples
SELECT ST_AsText(ST_Envelope('POINT(1 3)'::geometry));
st_astext
------------
POINT(1 3)
(1 row)
SELECT ST_AsText(ST_Envelope('LINESTRING(0 0, 1 3)'::geometry));
st_astext
--------------------------------
POLYGON((0 0,0 3,1 3,1 0,0 0))
(1 row)
SELECT ST_AsText(ST_Envelope('POLYGON((0 0, 0 1, 1.0000001 1, 1.0000001 0, 0 0))'::geometry));
st_astext
--------------------------------------------------------------
POLYGON((0 0,0 1,1.00000011920929 1,1.00000011920929 0,0 0))
(1 row)
SELECT ST_AsText(ST_Envelope('POLYGON((0 0, 0 1, 1.0000000001 1, 1.0000000001 0, 0 0))'::geometry));
st_astext
--------------------------------------------------------------
POLYGON((0 0,0 1,1.00000011920929 1,1.00000011920929 0,0 0))
(1 row)
SELECT Box3D(geom), Box2D(geom), ST_AsText(ST_Envelope(geom)) As envelopewkt
FROM (SELECT 'POLYGON((0 0, 0 1000012333334.34545678, 1.0000001 1, 1.0000001 0, 0 0))'::geometry As geom) As foo;
See Also, ST_ExteriorRingReturns a line string representing the exterior ring of the POLYGON geometry. Return
NULL if the geometry is not a polygon. Will not work with MULTIPOLYGONgeometry ST_ExteriorRinggeometry a_polygonDescriptionReturns a line string representing the exterior ring of the POLYGON geometry. Return
NULL if the geometry is not a polygon.Only works with POLYGON geometry types&sfs_compliant; 2.1.5.1&sqlmm_compliant; SQL-MM 3: 8.2.3, 8.3.3&Z_support;Examples
--If you have a table of polygons
SELECT gid, ST_ExteriorRing(the_geom) AS ering
FROM sometable;
--If you have a table of MULTIPOLYGONs
--and want to return a MULTILINESTRING composed of the exterior rings of each polygon
SELECT gid, ST_Collect(ST_ExteriorRing(the_geom)) AS erings
FROM (SELECT gid, (ST_Dump(the_geom)).geom As the_geom
FROM sometable) As foo
GROUP BY gid;
--3d Example
SELECT ST_AsEWKT(
ST_ExteriorRing(
ST_GeomFromEWKT('POLYGON((0 0 1, 1 1 1, 1 2 1, 1 1 1, 0 0 1))')
)
);
st_asewkt
---------
LINESTRING(0 0 1,1 1 1,1 2 1,1 1 1,0 0 1)
See Also,
,
ST_GeometryNReturn the 1-based Nth geometry if the geometry is a
GEOMETRYCOLLECTION, (MULTI)POINT, (MULTI)LINESTRING, MULTICURVE or (MULTI)POLYGON, POLYHEDRALSURFACE
Otherwise, return NULL.geometry ST_GeometryNgeometry geomAinteger nDescriptionReturn the 1-based Nth geometry if the geometry is a
GEOMETRYCOLLECTION, (MULTI)POINT, (MULTI)LINESTRING, MULTICURVE or (MULTI)POLYGON, POLYHEDRALSURFACE
Otherwise, return NULLIndex is 1-based as for OGC specs since version 0.8.0.
Previous versions implemented this as 0-based instead.If you want to extract all geometries, of a geometry, ST_Dump is more efficient and will also work for singular geoms.Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.Changed: 2.0.0 Prior versions would return NULL for singular geometries. This was changed to return the geometry for ST_GeometryN(..,1) case.&sfs_compliant;&sqlmm_compliant; SQL-MM 3: 9.1.5&Z_support;&curve_support;&P_support;&T_support;Standard Examples--Extracting a subset of points from a 3d multipoint
SELECT n, ST_AsEWKT(ST_GeometryN(the_geom, n)) As geomewkt
FROM (
VALUES (ST_GeomFromEWKT('MULTIPOINT(1 2 7, 3 4 7, 5 6 7, 8 9 10)') ),
( ST_GeomFromEWKT('MULTICURVE(CIRCULARSTRING(2.5 2.5,4.5 2.5, 3.5 3.5), (10 11, 12 11))') )
)As foo(the_geom)
CROSS JOIN generate_series(1,100) n
WHERE n <= ST_NumGeometries(the_geom);
n | geomewkt
---+-----------------------------------------
1 | POINT(1 2 7)
2 | POINT(3 4 7)
3 | POINT(5 6 7)
4 | POINT(8 9 10)
1 | CIRCULARSTRING(2.5 2.5,4.5 2.5,3.5 3.5)
2 | LINESTRING(10 11,12 11)
--Extracting all geometries (useful when you want to assign an id)
SELECT gid, n, ST_GeometryN(the_geom, n)
FROM sometable CROSS JOIN generate_series(1,100) n
WHERE n <= ST_NumGeometries(the_geom);Polyhedral Surfaces, TIN and Triangle Examples-- Polyhedral surface example
-- Break a Polyhedral surface into its faces
SELECT ST_AsEWKT(ST_GeometryN(p_geom,3)) As geom_ewkt
FROM (SELECT ST_GeomFromEWKT('POLYHEDRALSURFACE(
((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)),
((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)),
((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)),
((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1))
)') AS p_geom ) AS a;
geom_ewkt
------------------------------------------
POLYGON((0 0 0,1 0 0,1 0 1,0 0 1,0 0 0))-- TIN --
SELECT ST_AsEWKT(ST_GeometryN(geom,2)) as wkt
FROM
(SELECT
ST_GeomFromEWKT('TIN (((
0 0 0,
0 0 1,
0 1 0,
0 0 0
)), ((
0 0 0,
0 1 0,
1 1 0,
0 0 0
))
)') AS geom
) AS g;
-- result --
wkt
-------------------------------------
TRIANGLE((0 0 0,0 1 0,1 1 0,0 0 0))See Also, ST_GeometryTypeReturn the geometry type of the ST_Geometry value.text ST_GeometryTypegeometry g1DescriptionReturns the type of the geometry as a string. EG: 'ST_Linestring', 'ST_Polygon','ST_MultiPolygon' etc. This function differs from GeometryType(geometry) in the case of the string and ST in front that is returned, as well as the fact that it will not indicate whether the geometry is measured.Enhanced: 2.0.0 support for Polyhedral surfaces was introduced.&sqlmm_compliant; SQL-MM 3: 5.1.4&Z_support;&P_support;ExamplesSELECT ST_GeometryType(ST_GeomFromText('LINESTRING(77.29 29.07,77.42 29.26,77.27 29.31,77.29 29.07)'));
--result
ST_LineStringSELECT ST_GeometryType(ST_GeomFromEWKT('POLYHEDRALSURFACE( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)),
((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)), ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)), ((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)) )'));
--result
ST_PolyhedralSurfaceSELECT ST_GeometryType(ST_GeomFromEWKT('POLYHEDRALSURFACE( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)),
((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)), ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)), ((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)) )'));
--result
ST_PolyhedralSurfaceSELECT ST_GeometryType(geom) as result
FROM
(SELECT
ST_GeomFromEWKT('TIN (((
0 0 0,
0 0 1,
0 1 0,
0 0 0
)), ((
0 0 0,
0 1 0,
1 1 0,
0 0 0
))
)') AS geom
) AS g;
result
--------
ST_Tin See AlsoST_InteriorRingNReturn the Nth interior linestring ring of the polygon geometry.
Return NULL if the geometry is not a polygon or the given N is out
of range.geometry ST_InteriorRingNgeometry a_polygoninteger nDescriptionReturn the Nth interior linestring ring of the polygon geometry.
Return NULL if the geometry is not a polygon or the given N is out
of range. index starts at 1.This will not work for MULTIPOLYGONs. Use in conjunction with ST_Dump for MULTIPOLYGONS&sfs_compliant;&sqlmm_compliant; SQL-MM 3: 8.2.6, 8.3.5&Z_support;Examples
SELECT ST_AsText(ST_InteriorRingN(the_geom, 1)) As the_geom
FROM (SELECT ST_BuildArea(
ST_Collect(ST_Buffer(ST_Point(1,2), 20,3),
ST_Buffer(ST_Point(1, 2), 10,3))) As the_geom
) as foo
See Also,
,
,
,
ST_IsClosedReturns TRUE if the
LINESTRING's start and end points are coincident. For Polyhedral surface is closed (volumetric).
boolean ST_IsClosedgeometry gDescriptionReturns TRUE if the LINESTRING's
start and end points are coincident. For Polyhedral Surfaces, it tells you if the surface is areal (open) or volumetric (closed).&sfs_compliant;&sqlmm_compliant; SQL-MM 3: 7.1.5, 9.3.3SQL-MM defines the result of
ST_IsClosed(NULL) to be 0, while
PostGIS returns NULL.&Z_support;&curve_support;Enhanced: 2.0.0 support for Polyhedral surfaces was introduced.&P_support;Line String and Point Examplespostgis=# SELECT ST_IsClosed('LINESTRING(0 0, 1 1)'::geometry);
st_isclosed
-------------
f
(1 row)
postgis=# SELECT ST_IsClosed('LINESTRING(0 0, 0 1, 1 1, 0 0)'::geometry);
st_isclosed
-------------
t
(1 row)
postgis=# SELECT ST_IsClosed('MULTILINESTRING((0 0, 0 1, 1 1, 0 0),(0 0, 1 1))'::geometry);
st_isclosed
-------------
f
(1 row)
postgis=# SELECT ST_IsClosed('POINT(0 0)'::geometry);
st_isclosed
-------------
t
(1 row)
postgis=# SELECT ST_IsClosed('MULTIPOINT((0 0), (1 1))'::geometry);
st_isclosed
-------------
t
(1 row)Polyhedral Surface Examples
-- A cube --
SELECT ST_IsClosed(ST_GeomFromEWKT('POLYHEDRALSURFACE( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)),
((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)), ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)), ((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)) )'));
st_isclosed
-------------
t
-- Same as cube but missing a side --
SELECT ST_IsClosed(ST_GeomFromEWKT('POLYHEDRALSURFACE( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)),
((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)), ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)) )'));
st_isclosed
-------------
f
See AlsoST_IsCollectionReturns TRUE if the argument is a
collection (MULTI*, GEOMETRYCOLLECTION, ...)
boolean ST_IsCollectiongeometry gDescriptionReturns TRUE if the geometry type of
the argument is either:
GEOMETRYCOLLECTIONMULTI{POINT,POLYGON,LINESTRING,CURVE,SURFACE}COMPOUNDCURVE
This function analyzes the type of the geometry. This means
that it will return TRUE on collections
that are empty or that contain a single element.
&Z_support;&curve_support;Examplespostgis=# SELECT ST_IsCollection('LINESTRING(0 0, 1 1)'::geometry);
st_iscollection
-------------
f
(1 row)
postgis=# SELECT ST_IsCollection('MULTIPOINT EMPTY'::geometry);
st_iscollection
-------------
t
(1 row)
postgis=# SELECT ST_IsCollection('MULTIPOINT((0 0))'::geometry);
st_iscollection
-------------
t
(1 row)
postgis=# SELECT ST_IsCollection('MULTIPOINT((0 0), (42 42))'::geometry);
st_iscollection
-------------
t
(1 row)
postgis=# SELECT ST_IsCollection('GEOMETRYCOLLECTION(POINT(0 0))'::geometry);
st_iscollection
-------------
t
(1 row)See AlsoST_IsEmptyReturns true if this Geometry is an empty geometrycollection, polygon, point etc.boolean ST_IsEmptygeometry geomADescriptionReturns true if this Geometry is an empty geometry. If
true, then this Geometry represents an empty geometry collection, polygon, point etc.SQL-MM defines the result of ST_IsEmpty(NULL) to be 0, while
PostGIS returns NULL.&sfs_compliant; s2.1.1.1&sqlmm_compliant; SQL-MM 3: 5.1.7&curve_support;Changed: 2.0.0 In prior versions of PostGIS ST_GeomFromText('GEOMETRYCOLLECTION(EMPTY)') was allowed. This is now illegal in PostGIS 2.0.0 to better conform with SQL/MM standardsExamples
SELECT ST_IsEmpty(ST_GeomFromText('GEOMETRYCOLLECTION EMPTY'));
st_isempty
------------
t
(1 row)
SELECT ST_IsEmpty(ST_GeomFromText('POLYGON EMPTY'));
st_isempty
------------
t
(1 row)
SELECT ST_IsEmpty(ST_GeomFromText('POLYGON((1 2, 3 4, 5 6, 1 2))'));
st_isempty
------------
f
(1 row)
SELECT ST_IsEmpty(ST_GeomFromText('POLYGON((1 2, 3 4, 5 6, 1 2))')) = false;
?column?
----------
t
(1 row)
SELECT ST_IsEmpty(ST_GeomFromText('CIRCULARSTRING EMPTY'));
st_isempty
------------
t
(1 row)
ST_IsRingReturns TRUE if this
LINESTRING is both closed and simple.boolean ST_IsRinggeometry gDescriptionReturns TRUE if this
LINESTRING is both
(ST_StartPoint(g)~=ST_Endpoint(g)) and (does not self intersect).&sfs_compliant; 2.1.5.1&sqlmm_compliant; SQL-MM 3: 7.1.6SQL-MM defines the result of
ST_IsRing(NULL) to be 0, while
PostGIS returns NULL.ExamplesSELECT ST_IsRing(the_geom), ST_IsClosed(the_geom), ST_IsSimple(the_geom)
FROM (SELECT 'LINESTRING(0 0, 0 1, 1 1, 1 0, 0 0)'::geometry AS the_geom) AS foo;
st_isring | st_isclosed | st_issimple
-----------+-------------+-------------
t | t | t
(1 row)
SELECT ST_IsRing(the_geom), ST_IsClosed(the_geom), ST_IsSimple(the_geom)
FROM (SELECT 'LINESTRING(0 0, 0 1, 1 0, 1 1, 0 0)'::geometry AS the_geom) AS foo;
st_isring | st_isclosed | st_issimple
-----------+-------------+-------------
f | t | f
(1 row)See Also, , ,
ST_IsSimpleReturns (TRUE) if this Geometry has no anomalous geometric
points, such as self intersection or self tangency.boolean ST_IsSimplegeometry geomADescriptionReturns true if this Geometry has no anomalous geometric
points, such as self intersection or self tangency. For more
information on the OGC's definition of geometry simplicity and validity, refer
to "Ensuring OpenGIS compliancy of geometries"SQL-MM defines the result of ST_IsSimple(NULL) to be 0,
while PostGIS returns NULL.&sfs_compliant; s2.1.1.1&sqlmm_compliant; SQL-MM 3: 5.1.8&Z_support;Examples SELECT ST_IsSimple(ST_GeomFromText('POLYGON((1 2, 3 4, 5 6, 1 2))'));
st_issimple
-------------
t
(1 row)
SELECT ST_IsSimple(ST_GeomFromText('LINESTRING(1 1,2 2,2 3.5,1 3,1 2,2 1)'));
st_issimple
-------------
f
(1 row)See AlsoST_IsValidReturns true if the
ST_Geometry is well formed.
boolean ST_IsValidgeometry gboolean ST_IsValidgeometry ginteger flagsDescriptionTest if an ST_Geometry value is well formed. For geometries that are invalid,
the PostgreSQL NOTICE will provide details of why it is not valid. For more
information on the OGC's definition of geometry simplicity and validity, refer
to "Ensuring OpenGIS compliancy of geometries"
SQL-MM defines the result of ST_IsValid(NULL) to be 0, while
PostGIS returns NULL.
The version accepting flags is available starting with 2.0.0
and requires GEOS >= 3.3.0. Such version does not print a NOTICE
explaining the invalidity.
Allowed flags are documented in .
&sfs_compliant;&sqlmm_compliant; SQL-MM 3: 5.1.9ExamplesSELECT ST_IsValid(ST_GeomFromText('LINESTRING(0 0, 1 1)')) As good_line,
ST_IsValid(ST_GeomFromText('POLYGON((0 0, 1 1, 1 2, 1 1, 0 0))')) As bad_poly
--results
NOTICE: Self-intersection at or near point 0 0
good_line | bad_poly
-----------+----------
t | f
See Also,
,
,
ST_IsValidReasonReturns text stating if a geometry is valid or not and if not valid, a reason why.text ST_IsValidReasongeometry geomAtext ST_IsValidReasongeometry geomAinteger flagsDescriptionReturns text stating if a geometry is valid or not an if not valid, a reason why.Useful in combination with ST_IsValid to generate a detailed report of invalid geometries and reasons.
Allowed flags are documented in .
Availability: 1.4 - requires GEOS >= 3.1.0.Availability: 2.0 - requires GEOS >= 3.3.0 for the version taking flags.Examples
--First 3 Rejects from a successful quintuplet experiment
SELECT gid, ST_IsValidReason(the_geom) as validity_info
FROM
(SELECT ST_MakePolygon(ST_ExteriorRing(e.buff), ST_Accum(f.line)) As the_geom, gid
FROM (SELECT ST_Buffer(ST_MakePoint(x1*10,y1), z1) As buff, x1*10 + y1*100 + z1*1000 As gid
FROM generate_series(-4,6) x1
CROSS JOIN generate_series(2,5) y1
CROSS JOIN generate_series(1,8) z1
WHERE x1 > y1*0.5 AND z1 < x1*y1) As e
INNER JOIN (SELECT ST_Translate(ST_ExteriorRing(ST_Buffer(ST_MakePoint(x1*10,y1), z1)),y1*1, z1*2) As line
FROM generate_series(-3,6) x1
CROSS JOIN generate_series(2,5) y1
CROSS JOIN generate_series(1,10) z1
WHERE x1 > y1*0.75 AND z1 < x1*y1) As f
ON (ST_Area(e.buff) > 78 AND ST_Contains(e.buff, f.line))
GROUP BY gid, e.buff) As quintuplet_experiment
WHERE ST_IsValid(the_geom) = false
ORDER BY gid
LIMIT 3;
gid | validity_info
------+--------------------------
5330 | Self-intersection [32 5]
5340 | Self-intersection [42 5]
5350 | Self-intersection [52 5]
--simple example
SELECT ST_IsValidReason('LINESTRING(220227 150406,2220227 150407,222020 150410)');
st_isvalidreason
------------------
Valid Geometry
See Also, ST_IsValidDetailReturns a valid_detail (valid,reason,location) row stating if a geometry is valid or not and if not valid, a reason why and a location where.valid_detail ST_IsValidDetailgeometry geomvalid_detail ST_IsValidDetailgeometry geominteger flagsDescriptionReturns a valid_detail row, formed by a boolean (valid) stating if a geometry is valid, a varchar (reason) stating a reason why it is invalid and a geometry (location) pointing out where it is invalid.Useful to substitute and improve the combination of ST_IsValid and ST_IsValidReason to generate a detailed report of invalid geometries.
The 'flags' argument is a bitfield. It can have the following values:
1: Consider self-intersecting rings forming holes as valid.
This is also know as "the ESRI flag".
Note that this is against the OGC model.
Availability: 2.0.0 - requires GEOS >= 3.3.0.Examples
--First 3 Rejects from a successful quintuplet experiment
SELECT gid, reason(ST_IsValidDetail(the_geom)), ST_AsText(location(ST_IsValidDetail(the_geom))) as location
FROM
(SELECT ST_MakePolygon(ST_ExteriorRing(e.buff), ST_Accum(f.line)) As the_geom, gid
FROM (SELECT ST_Buffer(ST_MakePoint(x1*10,y1), z1) As buff, x1*10 + y1*100 + z1*1000 As gid
FROM generate_series(-4,6) x1
CROSS JOIN generate_series(2,5) y1
CROSS JOIN generate_series(1,8) z1
WHERE x1 > y1*0.5 AND z1 < x1*y1) As e
INNER JOIN (SELECT ST_Translate(ST_ExteriorRing(ST_Buffer(ST_MakePoint(x1*10,y1), z1)),y1*1, z1*2) As line
FROM generate_series(-3,6) x1
CROSS JOIN generate_series(2,5) y1
CROSS JOIN generate_series(1,10) z1
WHERE x1 > y1*0.75 AND z1 < x1*y1) As f
ON (ST_Area(e.buff) > 78 AND ST_Contains(e.buff, f.line))
GROUP BY gid, e.buff) As quintuplet_experiment
WHERE ST_IsValid(the_geom) = false
ORDER BY gid
LIMIT 3;
gid | reason | location
------+-------------------+-------------
5330 | Self-intersection | POINT(32 5)
5340 | Self-intersection | POINT(42 5)
5350 | Self-intersection | POINT(52 5)
--simple example
SELECT * FROM ST_IsValidDetail('LINESTRING(220227 150406,2220227 150407,222020 150410)');
valid | reason | location
-------+--------+----------
t | |
See Also,
ST_MReturn the M coordinate of the point, or NULL if not
available. Input must be a point.float ST_Mgeometry a_pointDescriptionReturn the M coordinate of the point, or NULL if not
available. Input must be a point.This is not (yet) part of the OGC spec, but is listed here
to complete the point coordinate extractor function list.&sfs_compliant;&sqlmm_compliant;&Z_support;ExamplesSELECT ST_M(ST_GeomFromEWKT('POINT(1 2 3 4)'));
st_m
------
4
(1 row)
See Also, , , ST_NDimsReturns coordinate dimension of the geometry as a small int.
Values are: 2,3 or 4.integer ST_NDimsgeometry g1DescriptionReturns the coordinate dimension of the geometry. PostGIS supports 2 - (x,y) ,
3 - (x,y,z) or 2D with measure - x,y,m, and 4 - 3D with measure space x,y,z,m&Z_support;ExamplesSELECT ST_NDims(ST_GeomFromText('POINT(1 1)')) As d2point,
ST_NDims(ST_GeomFromEWKT('POINT(1 1 2)')) As d3point,
ST_NDims(ST_GeomFromEWKT('POINTM(1 1 0.5)')) As d2pointm;
d2point | d3point | d2pointm
---------+---------+----------
2 | 3 | 3
See Also, , ST_NPointsReturn the number of points (vertexes) in a geometry.integer ST_NPointsgeometry g1DescriptionReturn the number of points in a geometry. Works for all geometries.Enhanced: 2.0.0 support for Polyhedral surfaces was introduced.Prior to 1.3.4, this function crashes if used with geometries that contain CURVES. This is fixed in 1.3.4+&Z_support;&curve_support;&P_support;ExamplesSELECT ST_NPoints(ST_GeomFromText('LINESTRING(77.29 29.07,77.42 29.26,77.27 29.31,77.29 29.07)'));
--result
4
--Polygon in 3D space
SELECT ST_NPoints(ST_GeomFromEWKT('LINESTRING(77.29 29.07 1,77.42 29.26 0,77.27 29.31 -1,77.29 29.07 3)'))
--result
4See AlsoST_NRingsIf the geometry is a polygon or multi-polygon returns the number of rings.integer ST_NRingsgeometry geomADescriptionIf the geometry is a polygon or multi-polygon returns the number of rings. Unlike NumInteriorRings, it counts
the outer rings as well.&Z_support;&curve_support;ExamplesSELECT ST_NRings(the_geom) As Nrings, ST_NumInteriorRings(the_geom) As ninterrings
FROM (SELECT ST_GeomFromText('POLYGON((1 2, 3 4, 5 6, 1 2))') As the_geom) As foo;
nrings | ninterrings
--------+-------------
1 | 0
(1 row)
See AlsoST_NumGeometriesIf geometry is a GEOMETRYCOLLECTION (or MULTI*) return the
number of geometries, for single geometries will return 1, otherwise return NULL.integer ST_NumGeometriesgeometry geomDescriptionReturns the number of Geometries. If geometry is a GEOMETRYCOLLECTION (or MULTI*) return the
number of geometries, for single geometries will return 1, otherwise return NULL.Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.Changed: 2.0.0 In prior versions this would return NULL if the geometry was not a collection/MULTI type.
2.0.0+ now returns 1 for single geometries e.g POLYGON, LINESTRING, POINT.&sqlmm_compliant; SQL-MM 3: 9.1.4&Z_support;&P_support;&T_support;Examples
--Prior versions would have returned NULL for this -- in 2.0.0 this returns 1
SELECT ST_NumGeometries(ST_GeomFromText('LINESTRING(77.29 29.07,77.42 29.26,77.27 29.31,77.29 29.07)'));
--result
1
--Geometry Collection Example - multis count as one geom in a collection
SELECT ST_NumGeometries(ST_GeomFromEWKT('GEOMETRYCOLLECTION(MULTIPOINT(-2 3 , -2 2),
LINESTRING(5 5 ,10 10),
POLYGON((-7 4.2,-7.1 5,-7.1 4.3,-7 4.2)))'));
--result
3
See Also, ST_NumInteriorRingsReturn the number of interior rings of the first polygon in
the geometry. This will work with both POLYGON and MULTIPOLYGON types but only looks at the first polygon.
Return NULL if there is no polygon in the
geometry.integer ST_NumInteriorRingsgeometry a_polygonDescriptionReturn the number of interior rings of the first polygon in
the geometry. This will work with both POLYGON and MULTIPOLYGON types but only looks at the first polygon.
Return NULL if there is no polygon in the
geometry.&sqlmm_compliant; SQL-MM 3: 8.2.5Examples
--If you have a regular polygon
SELECT gid, field1, field2, ST_NumInteriorRings(the_geom) AS numholes
FROM sometable;
--If you have multipolygons
--And you want to know the total number of interior rings in the MULTIPOLYGON
SELECT gid, field1, field2, SUM(ST_NumInteriorRings(the_geom)) AS numholes
FROM (SELECT gid, field1, field2, (ST_Dump(the_geom)).geom As the_geom
FROM sometable) As foo
GROUP BY gid, field1,field2;
See AlsoST_NumInteriorRingReturn the number of interior rings of the first polygon in
the geometry. Synonym to ST_NumInteriorRings. integer ST_NumInteriorRinggeometry a_polygonDescriptionReturn the number of interior rings of the first polygon in
the geometry. Synonym to ST_NumInteriorRings. The OpenGIS specs are
ambiguous about the exact function naming, so we provide both
spellings.&sqlmm_compliant; SQL-MM 3: 8.2.5See AlsoST_NumPatchesReturn the number of faces on a Polyhedral Surface. Will return null for non-polyhedral geometries.integer ST_NumPatchesgeometry g1DescriptionReturn the number of faces on a Polyhedral Surface. Will return null for non-polyhedral geometries. This is
an alias for ST_NumGeometries to support MM naming. Faster to use ST_NumGeometries if you don't care about MM convention.Availability: 2.0.0&Z_support;&sfs_compliant;&sqlmm_compliant; SQL-MM 3: ?&P_support;ExamplesSELECT ST_NumPatches(ST_GeomFromEWKT('POLYHEDRALSURFACE( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)),
((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)), ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)), ((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)) )'));
--result
6
See Also, ST_NumPointsReturn the number of points in an ST_LineString or
ST_CircularString value.integer ST_NumPointsgeometry g1DescriptionReturn the number of points in an ST_LineString or
ST_CircularString value. Prior to 1.4 only works with Linestrings as the specs state. From 1.4 forward this is an alias for ST_NPoints which returns number of vertexes for
not just line strings.
Consider using ST_NPoints instead which is multi-purpose
and works with many geometry types.&sfs_compliant;&sqlmm_compliant; SQL-MM 3: 7.2.4ExamplesSELECT ST_NumPoints(ST_GeomFromText('LINESTRING(77.29 29.07,77.42 29.26,77.27 29.31,77.29 29.07)'));
--result
4
See AlsoST_PatchNReturn the 1-based Nth geometry (face) if the geometry is a
POLYHEDRALSURFACE, POLYHEDRALSURFACEM.
Otherwise, return NULL.geometry ST_PatchNgeometry geomAinteger nDescription>Return the 1-based Nth geometry (face) if the geometry is a
POLYHEDRALSURFACE, POLYHEDRALSURFACEM.
Otherwise, return NULL. This returns the same answer as ST_GeometryN for Polyhedral Surfaces.
Using ST_GemoetryN is faster.Index is 1-based.If you want to extract all geometries, of a geometry, ST_Dump is more efficient.Availability: 2.0.0&sqlmm_compliant; SQL-MM 3: ?&Z_support;&P_support;Examples
--Extract the 2nd face of the polyhedral surface
SELECT ST_AsEWKT(ST_PatchN(geom, 2)) As geomewkt
FROM (
VALUES (ST_GeomFromEWKT('POLYHEDRALSURFACE( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)),
((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)), ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)),
((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)),
((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)), ((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)) )')) ) As foo(geom);
geomewkt
---+-----------------------------------------
POLYGON((0 0 0,0 1 0,1 1 0,1 0 0,0 0 0))
See Also, , , , ST_PointNReturn the Nth point in the first linestring or circular linestring in the
geometry. Return NULL if there is no linestring in the
geometry.geometry ST_PointNgeometry a_linestringinteger nDescriptionReturn the Nth point in the first linestring or circular linestring in the
geometry. Return NULL if there is no linestring in the
geometry.Index is 1-based as for OGC specs since version 0.8.0.
Previous versions implemented this as 0-based instead.If you want to get the nth point of each line string in a multilinestring, use in conjunction
with ST_Dump&sfs_compliant;&sqlmm_compliant; SQL-MM 3: 7.2.5, 7.3.5&Z_support;&curve_support;Examples-- Extract all POINTs from a LINESTRING
SELECT ST_AsText(
ST_PointN(
column1,
generate_series(1, ST_NPoints(column1))
))
FROM ( VALUES ('LINESTRING(0 0, 1 1, 2 2)'::geometry) ) AS foo;
st_astext
------------
POINT(0 0)
POINT(1 1)
POINT(2 2)
(3 rows)
--Example circular string
SELECT ST_AsText(ST_PointN(ST_GeomFromText('CIRCULARSTRING(1 2, 3 2, 1 2)'),2));
st_astext
----------
POINT(3 2)
See AlsoST_SRIDReturns the spatial reference identifier for the ST_Geometry as defined in spatial_ref_sys table.integer ST_SRIDgeometry g1DescriptionReturns the spatial reference identifier for the ST_Geometry as defined in spatial_ref_sys table. spatial_ref_sys
table is a table that catalogs all spatial reference systems known to PostGIS and is used for transformations from one spatial
reference system to another. So verifying you have the right spatial reference system identifier is important if you plan to ever transform your geometries.&sfs_compliant; s2.1.1.1&sqlmm_compliant; SQL-MM 3: 5.1.5&curve_support;ExamplesSELECT ST_SRID(ST_GeomFromText('POINT(-71.1043 42.315)',4326));
--result
4326
See Also, , , ST_StartPointReturns the first point of a LINESTRING
geometry as a POINT.geometry ST_StartPointgeometry geomADescriptionReturns the first point of a LINESTRING geometry
as a POINT or NULL if the input
parameter is not a LINESTRING.&sqlmm_compliant; SQL-MM 3: 7.1.3&Z_support;Changed: 2.0.0 no longer works with single geometry multilinestrings. In older
versions of PostGIS -- a single line multilinestring would work happily with this
function and return the start point. In 2.0.0 it just returns NULL like any other multilinestring.
The older behavior was an undocumented feature, but people who assumed they had their data stored as LINESTRING
may experience these returning NULL in 2.0 now.ExamplesSELECT ST_AsText(ST_StartPoint('LINESTRING(0 1, 0 2)'::geometry));
st_astext
------------
POINT(0 1)
(1 row)
SELECT ST_StartPoint('POINT(0 1)'::geometry) IS NULL AS is_null;
is_null
----------
t
(1 row)
--3d line
SELECT ST_AsEWKT(ST_StartPoint('LINESTRING(0 1 1, 0 2 2)'::geometry));
st_asewkt
------------
POINT(0 1 1)
(1 row)
See Also, ST_Summary
Returns a text summary of the contents of the geometry.
text ST_Summarygeometry gtext ST_Summarygeography gDescriptionReturns a text summary of the contents of the geometry.
Flags shown square brackets after the geometry type
have the following meaning:
M: has M ordinateZ: has Z ordinateB: has a cached bounding boxG: is geodetic (geography)Availability: 1.2.2 - 2.0.0 added support for geographyExamples
=# SELECT ST_Summary(ST_GeomFromText('LINESTRING(0 0, 1 1)')) as geom,
ST_Summary(ST_GeogFromText('POLYGON((0 0, 1 1, 1 2, 1 1, 0 0))')) geog;
geom | geog
-----------------------------+--------------------------
LineString[B] with 2 points | Polygon[BG] with 1 rings
: ring 0 has 5 points
:
(1 row)
=# SELECT ST_Summary(ST_GeogFromText('LINESTRING(0 0 1, 1 1 1)')) As geog_line,
ST_Summary(ST_GeomFromText('POLYGON((0 0 1, 1 1 2, 1 2 3, 1 1 1, 0 0 1))')) As geom_poly;
;
geog_line | geom_poly
-------------------------------+--------------------------
LineString[ZBG] with 2 points | Polygon[ZB] with 1 rings
: ring 0 has 5 points
:
(1 row)
See Also,
,
,
,
,
,
,
,
ST_XReturn the X coordinate of the point, or NULL if not
available. Input must be a point.float ST_Xgeometry a_pointDescriptionReturn the X coordinate of the point, or NULL if not
available. Input must be a point.If you want to get the max min x values of any geometry look at ST_XMin, ST_XMax functions.&sqlmm_compliant; SQL-MM 3: 6.1.3&Z_support;ExamplesSELECT ST_X(ST_GeomFromEWKT('POINT(1 2 3 4)'));
st_x
------
1
(1 row)
SELECT ST_Y(ST_Centroid(ST_GeomFromEWKT('LINESTRING(1 2 3 4, 1 1 1 1)')));
st_y
------
1.5
(1 row)
See Also, , , , , , ST_XMaxReturns X maxima of a bounding box 2d or 3d or a geometry.float ST_XMaxbox3d aGeomorBox2DorBox3DDescriptionReturns X maxima of a bounding box 2d or 3d or a geometry.Although this function is only defined for box3d, it will work for box2d and geometry because of the auto-casting behavior
defined for geometries and box2d. However you can not feed it a geometry or box2d text representation, since that will not auto-cast.&Z_support;&curve_support;ExamplesSELECT ST_XMax('BOX3D(1 2 3, 4 5 6)');
st_xmax
-------
4
SELECT ST_XMax(ST_GeomFromText('LINESTRING(1 3 4, 5 6 7)'));
st_xmax
-------
5
SELECT ST_XMax(CAST('BOX(-3 2, 3 4)' As box2d));
st_xmax
-------
3
--Observe THIS DOES NOT WORK because it will try to autocast the string representation to a BOX3D
SELECT ST_XMax('LINESTRING(1 3, 5 6)');
--ERROR: BOX3D parser - doesnt start with BOX3D(
SELECT ST_XMax(ST_GeomFromEWKT('CIRCULARSTRING(220268 150415 1,220227 150505 2,220227 150406 3)'));
st_xmax
--------
220288.248780547
See Also, , , , ST_XMinReturns X minima of a bounding box 2d or 3d or a geometry.float ST_XMinbox3d aGeomorBox2DorBox3DDescriptionReturns X minima of a bounding box 2d or 3d or a geometry.Although this function is only defined for box3d, it will work for box2d and geometry because of the auto-casting behavior
defined for geometries and box2d. However you can not feed it a geometry or box2d text representation, since that will not auto-cast.&Z_support;&curve_support;ExamplesSELECT ST_XMin('BOX3D(1 2 3, 4 5 6)');
st_xmin
-------
1
SELECT ST_XMin(ST_GeomFromText('LINESTRING(1 3 4, 5 6 7)'));
st_xmin
-------
1
SELECT ST_XMin(CAST('BOX(-3 2, 3 4)' As box2d));
st_xmin
-------
-3
--Observe THIS DOES NOT WORK because it will try to autocast the string representation to a BOX3D
SELECT ST_XMin('LINESTRING(1 3, 5 6)');
--ERROR: BOX3D parser - doesnt start with BOX3D(
SELECT ST_XMin(ST_GeomFromEWKT('CIRCULARSTRING(220268 150415 1,220227 150505 2,220227 150406 3)'));
st_xmin
--------
220186.995121892
See Also, , , , ST_YReturn the Y coordinate of the point, or NULL if not
available. Input must be a point.float ST_Ygeometry a_pointDescriptionReturn the Y coordinate of the point, or NULL if not
available. Input must be a point.&sfs_compliant;&sqlmm_compliant; SQL-MM 3: 6.1.4&Z_support;ExamplesSELECT ST_Y(ST_GeomFromEWKT('POINT(1 2 3 4)'));
st_y
------
2
(1 row)
SELECT ST_Y(ST_Centroid(ST_GeomFromEWKT('LINESTRING(1 2 3 4, 1 1 1 1)')));
st_y
------
1.5
(1 row)
See Also, , , , , , ST_YMaxReturns Y maxima of a bounding box 2d or 3d or a geometry.float ST_YMaxbox3d aGeomorBox2DorBox3DDescriptionReturns Y maxima of a bounding box 2d or 3d or a geometry.Although this function is only defined for box3d, it will work for box2d and geometry because of the auto-casting behavior
defined for geometries and box2d. However you can not feed it a geometry or box2d text representation, since that will not auto-cast.&Z_support;&curve_support;ExamplesSELECT ST_YMax('BOX3D(1 2 3, 4 5 6)');
st_ymax
-------
5
SELECT ST_YMax(ST_GeomFromText('LINESTRING(1 3 4, 5 6 7)'));
st_ymax
-------
6
SELECT ST_YMax(CAST('BOX(-3 2, 3 4)' As box2d));
st_ymax
-------
4
--Observe THIS DOES NOT WORK because it will try to autocast the string representation to a BOX3D
SELECT ST_YMax('LINESTRING(1 3, 5 6)');
--ERROR: BOX3D parser - doesnt start with BOX3D(
SELECT ST_YMax(ST_GeomFromEWKT('CIRCULARSTRING(220268 150415 1,220227 150505 2,220227 150406 3)'));
st_ymax
--------
150506.126829327
See Also, , , , ST_YMinReturns Y minima of a bounding box 2d or 3d or a geometry.float ST_YMinbox3d aGeomorBox2DorBox3DDescriptionReturns Y minima of a bounding box 2d or 3d or a geometry.Although this function is only defined for box3d, it will work for box2d and geometry because of the auto-casting behavior
defined for geometries and box2d. However you can not feed it a geometry or box2d text representation, since that will not auto-cast.&Z_support;&curve_support;ExamplesSELECT ST_YMin('BOX3D(1 2 3, 4 5 6)');
st_ymin
-------
2
SELECT ST_YMin(ST_GeomFromText('LINESTRING(1 3 4, 5 6 7)'));
st_ymin
-------
3
SELECT ST_YMin(CAST('BOX(-3 2, 3 4)' As box2d));
st_ymin
-------
2
--Observe THIS DOES NOT WORK because it will try to autocast the string representation to a BOX3D
SELECT ST_YMin('LINESTRING(1 3, 5 6)');
--ERROR: BOX3D parser - doesnt start with BOX3D(
SELECT ST_YMin(ST_GeomFromEWKT('CIRCULARSTRING(220268 150415 1,220227 150505 2,220227 150406 3)'));
st_ymin
--------
150406
See Also, , , , , ST_ZReturn the Z coordinate of the point, or NULL if not
available. Input must be a point.float ST_Zgeometry a_pointDescriptionReturn the Z coordinate of the point, or NULL if not
available. Input must be a point.&sqlmm_compliant;&Z_support;ExamplesSELECT ST_Z(ST_GeomFromEWKT('POINT(1 2 3 4)'));
st_z
------
3
(1 row)
See Also, , , , , ST_ZMaxReturns Z minima of a bounding box 2d or 3d or a geometry.float ST_ZMaxbox3d aGeomorBox2DorBox3DDescriptionReturns Z maxima of a bounding box 2d or 3d or a geometry.Although this function is only defined for box3d, it will work for box2d and geometry because of the auto-casting behavior
defined for geometries and box2d. However you can not feed it a geometry or box2d text representation, since that will not auto-cast.&Z_support;&curve_support;ExamplesSELECT ST_ZMax('BOX3D(1 2 3, 4 5 6)');
st_zmax
-------
6
SELECT ST_ZMax(ST_GeomFromEWKT('LINESTRING(1 3 4, 5 6 7)'));
st_zmax
-------
7
SELECT ST_ZMax('BOX3D(-3 2 1, 3 4 1)' );
st_zmax
-------
1
--Observe THIS DOES NOT WORK because it will try to autocast the string representation to a BOX3D
SELECT ST_ZMax('LINESTRING(1 3 4, 5 6 7)');
--ERROR: BOX3D parser - doesnt start with BOX3D(
SELECT ST_ZMax(ST_GeomFromEWKT('CIRCULARSTRING(220268 150415 1,220227 150505 2,220227 150406 3)'));
st_zmax
--------
3
See Also, , , , , ST_ZmflagReturns ZM (dimension semantic) flag of the geometries as a
small int. Values are: 0=2d, 1=3dm, 2=3dz, 3=4d.smallint ST_Zmflaggeometry geomADescriptionReturns ZM (dimension semantic) flag of the geometries as a
small int. Values are: 0=2d, 1=3dm, 2=3dz, 3=4d.&Z_support;&curve_support;ExamplesSELECT ST_Zmflag(ST_GeomFromEWKT('LINESTRING(1 2, 3 4)'));
st_zmflag
-----------
0
SELECT ST_Zmflag(ST_GeomFromEWKT('LINESTRINGM(1 2 3, 3 4 3)'));
st_zmflag
-----------
1
SELECT ST_Zmflag(ST_GeomFromEWKT('CIRCULARSTRING(1 2 3, 3 4 3, 5 6 3)'));
st_zmflag
-----------
2
SELECT ST_Zmflag(ST_GeomFromEWKT('POINT(1 2 3 4)'));
st_zmflag
-----------
3
See Also, , ST_ZMinReturns Z minima of a bounding box 2d or 3d or a geometry.float ST_ZMinbox3d aGeomorBox2DorBox3DDescriptionReturns Z minima of a bounding box 2d or 3d or a geometry.Although this function is only defined for box3d, it will work for box2d and geometry because of the auto-casting behavior
defined for geometries and box2d. However you can not feed it a geometry or box2d text representation, since that will not auto-cast.&Z_support;&curve_support;ExamplesSELECT ST_ZMin('BOX3D(1 2 3, 4 5 6)');
st_zmin
-------
3
SELECT ST_ZMin(ST_GeomFromEWKT('LINESTRING(1 3 4, 5 6 7)'));
st_zmin
-------
4
SELECT ST_ZMin('BOX3D(-3 2 1, 3 4 1)' );
st_zmin
-------
1
--Observe THIS DOES NOT WORK because it will try to autocast the string representation to a BOX3D
SELECT ST_ZMin('LINESTRING(1 3 4, 5 6 7)');
--ERROR: BOX3D parser - doesnt start with BOX3D(
SELECT ST_ZMin(ST_GeomFromEWKT('CIRCULARSTRING(220268 150415 1,220227 150505 2,220227 150406 3)'));
st_zmin
--------
1
See Also, , , , , ,