ST_Accum Aggregate. Constructs an array of geometries. geometry[] ST_Accum geometry set geomfield Aggregate. Constructs an array of geometries. Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced. &Z_support; &curve_support; &P_support; &T_support; SELECT (ST_Accum(the_geom)) As all_em, ST_AsText((ST_Accum(the_geom))[1]) As grabone, (ST_Accum(the_geom))[2:4] as grab_rest FROM (SELECT ST_MakePoint(a*CAST(random()*10 As integer), a*CAST(random()*10 As integer), a*CAST(random()*10 As integer)) As the_geom FROM generate_series(1,4) a) As foo; all_em|grabone | grab_rest -------------------------------------------------------------------------------+ {0101000080000000000000144000000000000024400000000000001040: 0101000080000000000 00018400000000000002C400000000000003040: 0101000080000000000000354000000000000038400000000000001840: 010100008000000000000040400000000000003C400000000000003040} | POINT(5 10) | {010100008000000000000018400000000000002C400000000000003040: 0101000080000000000000354000000000000038400000000000001840: 010100008000000000000040400000000000003C400000000000003040} (1 row) Box2D Returns a BOX2D representing the maximum extents of the geometry. box2d Box2D geometry geomA Returns a BOX2D representing the maximum extents of the geometry. Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced. &curve_support; &P_support; &T_support; SELECT Box2D(ST_GeomFromText('LINESTRING(1 2, 3 4, 5 6)')); box2d --------- BOX(1 2,5 6) SELECT Box2D(ST_GeomFromText('CIRCULARSTRING(220268 150415,220227 150505,220227 150406)')); box2d -------- BOX(220186.984375 150406,220288.25 150506.140625) , Box3D Returns a BOX3D representing the maximum extents of the geometry. box3d Box3D geometry geomA Returns a BOX3D representing the maximum extents of the geometry. Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced. &curve_support; &P_support; &T_support; &Z_support; SELECT Box3D(ST_GeomFromEWKT('LINESTRING(1 2 3, 3 4 5, 5 6 5)')); Box3d --------- BOX3D(1 2 3,5 6 5) SELECT Box3D(ST_GeomFromEWKT('CIRCULARSTRING(220268 150415 1,220227 150505 1,220227 150406 1)')); Box3d -------- BOX3D(220227 150406 1,220268 150415 1) , ST_Estimated_Extent Return the 'estimated' extent of the given spatial table. The estimated is taken from the geometry column's statistics. The current schema will be used if not specified. box2d ST_Estimated_Extent text schema_name text table_name text geocolumn_name box2d ST_Estimated_Extent text table_name text geocolumn_name Return the 'estimated' extent of the given spatial table. The estimated is taken from the geometry column's statistics. The current schema will be used if not specified. For PostgreSQL>=8.0.0 statistics are gathered by VACUUM ANALYZE and resulting extent will be about 95% of the real one. In absence of statistics (empty table or no ANALYZE called) this function returns NULL. Prior to version 1.5.4 an exception was thrown instead. For PostgreSQL<8.0.0 statistics are gathered by update_geometry_stats() and resulting extent will be exact. Availability: 1.0.0 &curve_support; SELECT ST_Estimated_extent('ny', 'edges', 'the_geom'); --result-- BOX(-8877653 4912316,-8010225.5 5589284) SELECT ST_Estimated_Extent('feature_poly', 'the_geom'); --result-- BOX(-124.659652709961 24.6830825805664,-67.7798080444336 49.0012092590332) ST_Expand Returns bounding box expanded in all directions from the bounding box of the input geometry. Uses double-precision geometry ST_Expand geometry g1 float units_to_expand box2d ST_Expand box2d g1 float units_to_expand box3d ST_Expand box3d g1 float units_to_expand This function returns a bounding box expanded in all directions from the bounding box of the input geometry, by an amount specified in the second argument. Uses double-precision. Very useful for distance() queries, or bounding box queries to add an index filter to the query. There are 3 variants of this. The one that takes a geometry will return a POLYGON geometry representation of the bounding box and is the most commonly used variant. ST_Expand is similar in concept to ST_Buffer except while buffer expands the geometry in all directions, ST_Expand expands the bounding box an x,y,z unit amount. Units are in the units of the spatial reference system in use denoted by the SRID Pre 1.3, ST_Expand was used in conjunction with distance to do indexable queries. Something of the form the_geom && ST_Expand('POINT(10 20)', 10) AND ST_Distance(the_geom, 'POINT(10 20)') < 10 Post 1.2, this was replaced with the easier ST_DWithin construct. Bounding boxes of all geometries are currently 2-d even if they are 3-dimensional geometries. Availability: 1.5.0 behavior changed to output double precision instead of float4 coordinates. Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced. &P_support; &T_support; Examples below use US National Atlas Equal Area (SRID=2163) which is a meter projection --10 meter expanded box around bbox of a linestring SELECT CAST(ST_Expand(ST_GeomFromText('LINESTRING(2312980 110676,2312923 110701,2312892 110714)', 2163),10) As box2d); st_expand ------------------------------------ BOX(2312882 110666,2312990 110724) --10 meter expanded 3d box of a 3d box SELECT ST_Expand(CAST('BOX3D(778783 2951741 1,794875 2970042.61545891 10)' As box3d),10) st_expand ----------------------------------------------------- BOX3D(778773 2951731 -9,794885 2970052.61545891 20) --10 meter geometry astext rep of a expand box around a point geometry SELECT ST_AsEWKT(ST_Expand(ST_GeomFromEWKT('SRID=2163;POINT(2312980 110676)'),10)); st_asewkt ------------------------------------------------------------------------------------------------- SRID=2163;POLYGON((2312970 110666,2312970 110686,2312990 110686,2312990 110666,2312970 110666)) , , , , , ST_Extent an aggregate function that returns the bounding box that bounds rows of geometries. box2d ST_Extent geometry set geomfield ST_Extent returns a bounding box that encloses a set of geometries. The ST_Extent function is an "aggregate" function in the terminology of SQL. That means that it operates on lists of data, in the same way the SUM() and AVG() functions do. Since it returns a bounding box, the spatial Units are in the units of the spatial reference system in use denoted by the SRID ST_Extent is similar in concept to Oracle Spatial/Locator's SDO_AGGR_MBR Since ST_Extent returns a bounding box, the SRID meta-data is lost. Use ST_SetSRID to force it back into a geometry with SRID meta data. The coordinates are in the units of the spatial ref of the orginal geometries. ST_Extent will return boxes with only an x and y component even with (x,y,z) coordinate geometries. To maintain x,y,z use ST_3DExtent instead. Availability: 1.4.0 Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced. &P_support; &T_support; Examples below use Massachusetts State Plane ft (SRID=2249) SELECT ST_Extent(the_geom) as bextent FROM sometable; st_bextent ------------------------------------ BOX(739651.875 2908247.25,794875.8125 2970042.75) --Return extent of each category of geometries SELECT ST_Extent(the_geom) as bextent FROM sometable GROUP BY category ORDER BY category; bextent | name ----------------------------------------------------+---------------- BOX(778783.5625 2951741.25,794875.8125 2970042.75) | A BOX(751315.8125 2919164.75,765202.6875 2935417.25) | B BOX(739651.875 2917394.75,756688.375 2935866) | C --Force back into a geometry -- and render the extended text representation of that geometry SELECT ST_SetSRID(ST_Extent(the_geom),2249) as bextent FROM sometable; bextent -------------------------------------------------------------------------------- SRID=2249;POLYGON((739651.875 2908247.25,739651.875 2970042.75,794875.8125 2970042.75, 794875.8125 2908247.25,739651.875 2908247.25)) , , , ST_3DExtent an aggregate function that returns the box3D bounding box that bounds rows of geometries. box3d ST_3DExtent geometry set geomfield ST_3DExtent returns a box3d (includes Z coordinate) bounding box that encloses a set of geometries. The ST_3DExtent function is an "aggregate" function in the terminology of SQL. That means that it operates on lists of data, in the same way the SUM() and AVG() functions do. Since it returns a bounding box, the spatial Units are in the units of the spatial reference system in use denoted by the SRID Since ST_3DExtent returns a bounding box, the SRID meta-data is lost. Use ST_SetSRID to force it back into a geometry with SRID meta data. The coordinates are in the units of the spatial ref of the orginal geometries. Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced. Changed: 2.0.0 In prior versions this used to be called ST_Extent3D &Z_support; &curve_support; &P_support; &T_support; SELECT ST_3DExtent(foo.the_geom) As b3extent FROM (SELECT ST_MakePoint(x,y,z) As the_geom FROM generate_series(1,3) As x CROSS JOIN generate_series(1,2) As y CROSS JOIN generate_series(0,2) As Z) As foo; b3extent -------------------- BOX3D(1 1 0,3 2 2) --Get the extent of various elevated circular strings SELECT ST_3DExtent(foo.the_geom) As b3extent FROM (SELECT ST_Translate(ST_Force_3DZ(ST_LineToCurve(ST_Buffer(ST_MakePoint(x,y),1))),0,0,z) As the_geom FROM generate_series(1,3) As x CROSS JOIN generate_series(1,2) As y CROSS JOIN generate_series(0,2) As Z) As foo; b3extent -------------------- BOX3D(1 0 0,4 2 2) , Find_SRID The syntax is find_srid(<db/schema>, <table>, <column>) and the function returns the integer SRID of the specified column by searching through the GEOMETRY_COLUMNS table. integer Find_SRID varchar a_schema_name varchar a_table_name varchar a_geomfield_name The syntax is find_srid(<db/schema>, <table>, <column>) and the function returns the integer SRID of the specified column by searching through the GEOMETRY_COLUMNS table. If the geometry column has not been properly added with the AddGeometryColumns() function, this function will not work either. SELECT Find_SRID('public', 'tiger_us_state_2007', 'the_geom_4269'); find_srid ---------- 4269 ST_Mem_Size Returns the amount of space (in bytes) the geometry takes. integer ST_Mem_Size geometry geomA Returns the amount of space (in bytes) the geometry takes. This is a nice compliment to PostgreSQL built in functions pg_size_pretty, pg_relation_size, pg_total_relation_size. pg_relation_size which gives the byte size of a table may return byte size lower than ST_Mem_Size. This is because pg_relation_size does not add toasted table contribution and large geometries are stored in TOAST tables. pg_total_relation_size - includes, the table, the toasted tables, and the indexes. &Z_support; &curve_support; &P_support; &T_support; --Return how much byte space Boston takes up in our Mass data set SELECT pg_size_pretty(SUM(ST_Mem_Size(the_geom))) as totgeomsum, pg_size_pretty(SUM(CASE WHEN town = 'BOSTON' THEN st_mem_size(the_geom) ELSE 0 END)) As bossum, CAST(SUM(CASE WHEN town = 'BOSTON' THEN st_mem_size(the_geom) ELSE 0 END)*1.00 / SUM(st_mem_size(the_geom))*100 As numeric(10,2)) As perbos FROM towns; totgeomsum bossum perbos ---------- ------ ------ 1522 kB 30 kB 1.99 SELECT ST_Mem_Size(ST_GeomFromText('CIRCULARSTRING(220268 150415,220227 150505,220227 150406)')); --- 73 --What percentage of our table is taken up by just the geometry SELECT pg_total_relation_size('public.neighborhoods') As fulltable_size, sum(ST_Mem_Size(the_geom)) As geomsize, sum(ST_Mem_Size(the_geom))*1.00/pg_total_relation_size('public.neighborhoods')*100 As pergeom FROM neighborhoods; fulltable_size geomsize pergeom ------------------------------------------------ 262144 96238 36.71188354492187500000 ST_Point_Inside_Circle Is the point geometry insert circle defined by center_x, center_y, radius boolean ST_Point_Inside_Circle geometry a_point float center_x float center_y float radius The syntax for this functions is point_inside_circle(<geometry>,<circle_center_x>,<circle_center_y>,<radius>). Returns the true if the geometry is a point and is inside the circle. Returns false otherwise. This only works for points as the name suggests SELECT ST_Point_Inside_Circle(ST_Point(1,2), 0.5, 2, 3); st_point_inside_circle ------------------------ t