Geospatial Functions¶

Enhanced Performance Functions¶

The functions below all compare x and y coordinates to geometry objects (or vice versa), thus increasing their performance in queries. Each of these functions have a geometry-to-geometry version listed in the next section.

Function	Description
`STXY_CONTAINS(geom, x, y)`	Returns `1` (true) if `geom` contains the `x` and `y` coordinate, e.g. lies in the interior of `geom`. The coordinate cannot be on the boundary and also be contained because `geom` does not contain its boundary
`STXY_CONTAINSPROPERLY(x, y, geom)`	Returns `1` (true) if the `x` and `y` coordinate intersects the interior of `geom` but not the boundary (or exterior) because `geom` does not contain its boundary but does contain itself
`STXY_COVEREDBY(x, y, geom)`	Returns `1` (true) if the `x` and `y` coordinate is covered by `geom`
`STXY_COVERS(geom, x, y)`	Returns `1` (true) if `geom` covers the `x` and `y` coordinate
`STXY_DISJOINT(x, y, geom)`	Returns `1` (true) if the given `x` and `y` coordinate and the geometry `geom` do not spatially intersect.
`STXY_DISTANCE(x, y, geom)`	Returns the minimum 2-D Cartesian distance (in degrees) between the given `x` and `y` coordinate and `geom`.
`STXY_DWITHIN(x, y, geom, distance)`	Returns `1` (true) if the `x` and `y` coordinate is within the specified `distance` from `geom`.
`STXY_ENVDWITHIN(x, y, geom, distance)`	Returns `1` (true) if the `x` and `y` coordinate is within the specified `distance` from the bounding box of `geom`.
`STXY_ENVINTERSECTS(x, y, geom)`	Returns `1` (true) if the bounding box of the given geometry `geom` intersects the `x` and `y` coordinate.
`STXY_INTERSECTION(x, y, geom)`	Returns the shared portion between the `x` and `y` coordinate and the given geometry `geom`, i.e. the point itself.
`STXY_INTERSECTS(x, y, geom)`	Returns `1` (true) if the `x` and `y` coordinate and `geom` intersect in 2-D.
`STXY_TOUCHES(x, y, geom)`	Returns `1` (true) if the `x` and `y` coordinate and geometry `geom` have at least one point in common but their interiors do not intersect.
`STXY_WITHIN(x, y, geom)`	Returns `1` (true) if the `x` and `y` coordinate is completely inside the `geom` geometry i.e., not on the boundary

Geometry Functions¶

Function	Details
`DIST(x1, y1, x2, y2)`	Computes the Euclidean distance (in degrees), i.e. `SQRT( (x1-x2)(x1-x2) + (y1-y2)(y1-y2) )`.
`GEODIST(lon1, lat1, lon2, lat2)`	Computes the geographic great-circle distance (in meters) between two lat/lon points.
`ST_ADDPOINT(linestring, point, position)`	Adds a the given `point` geometry to the given `linestring` geometry at the specified `position`, which is a 0-based index.
`ST_ALMOSTEQUALS(geom1, geom2, decimal)`	Returns `1` (true) if given geometries, `geom1` and `geom2`, are almost spatially equal within the given amount of `decimal` scale. Note that geometries will still be considered equal if the decimal scale for the geometries is within a half order of magnitude of each other, e.g, if `decimal` is set to 2, then POINT(63.4 123.45) and POINT(63.4 123.454) are equal, but POINT(63.4 123.45) and POINT(63.4 123.459) are not equal. The geometry types must match to be considered equal.
`ST_AREA(geom)`	Returns the area of the given geometry `geom` (in degrees) if it is a POLYGON or MULTIPOLYGON. Returns `0` if the input geometry type is (MULTI)POINT or (MULTI)LINESTRING.
`ST_BOUNDARY(geom)`	Returns the closure of the combinatorial boundary of a given geometry `geom`. Returns an empty geometry if `geom` is an empty geometry. Returns a `null` if `geom` is a GEOMETRYCOLLECTION
`ST_BOUNDINGDIAGONAL(geom)`	Returns the diagonal of the given geometry's (`geom`) bounding box.
`ST_BUFFER(geom, radius, style)`	Returns a geometry that represents all points whose distance from the given geometry `geom` is less than or equal to the given distance `radius` in degrees. Additional `style` parameters can be specified as a list of blank-separated key-value pairs, e.g., `'quad_segs=8 endcap=round'` : `quad_segs` -- the number of segments used to approximate a quarter circle (default is `8`) `endcap` -- the endcap style of the buffer (default is `round`); options are `round`, `flat` (or `butt`), and `square` `join` -- the join style of the buffer (default is `round`); options are `round`, `mitre` (or `miter`), and `bevel` `mitre_limit` -- the mitre ratio limit expressed as a floating point number (`miter_limit` is also acceptable)
`ST_CENTROID(geom)`	Calculates the center of the given geometry `geom` as a POINT. For (MULTI)POINTs, the center is calculated as the average of the input coordinates. For (MULTI)LINESTRINGs, the center is calculated as the weighted length of each given LINESTRING. For (MULTI)POLYGONs, the center is calculated as the weighted area of each given POLYGON. If `geom` is an empty geometry, an empty GEOMETRYCOLLECTION is returned
`ST_CLIP(geom1, geom2)`	Returns the geometry shared between given geometries `geom1` and `geom2`.
`ST_COLLECTIONEXTRACT(collection, type)`	Returns only the specified `type` from the given geometry `collection`. Type is a number that maps to the following: `1` = `POINT` `2` = `LINESTRING` `3` = `POLYGON`
`ST_COLLECTIONHOMOGENIZE(collection)`	Returns the simplest form of the given `collection`, e.g., a collection with a single POINT will be returned as `POINT(x y)`, and a collection with multiple individual points will be returned as a MULTIPOINT.
`ST_CONTAINS(geom1, geom2)`	Returns `1` (true) if no points of `geom2` lie in the exterior of `geom1` and at least one point of `geom2` lies in the interior of `geom1`. Note that `geom1` does not contain its boundary but does contain itself.
`ST_CONTAINSPROPERLY(geom1, geom2)`	Returns `1` (true) if `geom2` intersects the interior of `geom1` but not the boundary (or exterior). Note that `geom1` does not contain its boundary but does contain itself.
`ST_CONVEXHULL(geom)`	Returns the minimum convex geometry that encloses all geometries in the given `geom` set.
`ST_COORDDIM(geom)`	Returns the coordinate dimension of the given `geom`, e.g., a geometry with `x`, `y`, and `z` coordinates would return `3`.
`ST_COVEREDBY(geom1, geom2)`	Returns `1` (true) if no point in `geom1` is outside `geom2`.
`ST_COVERS(geom1, geom2)`	Returns `1` (true) if no point in `geom2` is outside `geom1`.
`ST_CROSSES(geom1, geom2)`	Returns `1` (true) if the given geometries, `geom1` and `geom2`, spatially cross, meaning some but not all interior points in common.
`ST_DIFFERENCE(geom1, geom2)`	Returns a geometry that represents the part of `geom1` that does not intersect with `geom2`.
`ST_DIMENSION(geom)`	Returns the dimension of the given geometry `geom`, which is less than or equal to the coordinate dimension. If `geom` is a single geometry, a `0` is for `POINT`, a `1` is for `LINESTRING`, and a `2` is for `POLYGON`. If `geom` is a collection, it will return the largest dimension from the collection. If `geom` is empty, `0` is returned.
`ST_DISJOINT(geom1, geom2)`	Returns `1` (true) if the given geometries, `geom1` and `geom2`, do not spatially intersect.
`ST_DISTANCE(geom1, geom2)`	Returns the minimum 2-D Cartesian distance (in degrees) between the given geometries, `geom1` and `geom2`.
`ST_DWITHIN(geom1, geom2, distance)`	Returns `1` (true) if the geometries `geom1` and `geom2` are within the specified `distance` of each other.
`ST_ELLIPSE(centerx, centery, height, width)`	Returns an ellipse using the following values: `centerx` -- the x coordinate or longitude used to center the ellipse `centery` -- the y coordinate or latitude used to center the ellipse `height` -- the height of the ellipse (in degrees) `width` -- the width of the ellipse (in degrees)
`ST_ENDPOINT(geom)`	Returns the last point of the given `geom` as a POINT if it's a LINESTRING. If `geom` is not a a LINESTRING, `null` is returned.
`ST_ENVDWITHIN(geom1, geom2, distance)`	Returns `1` (true) if `geom1` is within the specified `distance` of the bounding box of `geom2`.
`ST_ENVELOPE(geom)`	Returns the bounding box of a given geometry `geom`.
`ST_ENVINTERSECTS(geom1, geom2)`	Returns `1` (true) if the bounding box of the given geometries, `geom1` and `geom2`, intersect.
`ST_EQUALS(geom1, geom2)`	Returns `1` (true) if the given geometries, `geom1` and `geom2`, are spatially equal. Note that order does not matter.
`ST_EQUALSEXACT(geom1, geom2, tolerance)`	Returns `1` (true) if the given geometries, `geom1` and `geom2`, are almost spatially equal within some given `tolerance`. If the values within the given geometries are within the `tolerance` value of each other, they're considered equal, e.g., if `tolerance` is 2, POINT(1 1) and POINT(1 3) are considered equal, but POINT(1 1) and POINT(1 3.1) are not. Note that the geometry types have to match for them to be considered equal.
`ST_ERASE(geom1, geom2)`	Returns the result of erasing a portion of `geom1` equal to the size of `geom2`.
`ST_EXPAND(geom, units)`	Returns the bounding box expanded in all directions by the given `units` of the given `geom`. The expansion can also be defined for separate directions by providing separate parameters for each direction, e.g., `ST_EXPAND(geom, unitsx, unitsy, unitsz, unitsm)`.
`ST_EXPANDBYRATE(geom, rate)`	Returns the bounding box expanded by a given `rate` (a ratio of width and height) for the given geometry `geom`. The `rate` must be between 0 and 1.
`ST_EXTERIORRING(geom)`	Returns a LINESTRING representing the exterior ring of the given POLYGON `geom`
`ST_GENERATEPOINTS(geom, num)`	Creates a MULTIPOINT containing a number `num` of randomly generated points within the boundary of `geom`.
`ST_GEOMETRYN(geom, index)`	Returns the `index` geometry back from the given `geom` geometry. The `index` starts from 1 to the number of geometry in `geom`.
`ST_GEOMETRYTYPE(geom)`	Returns the type of geometry from the given `geom`.
`ST_GEOMETRYTYPEID(geom)`	Returns the type ID of from `geom`. Type and ID mappings: POINT = 0 LINESTRING = 1 LINEARRING = 2 POLYGON = 3 MULTIPOINT = 4 MULTILINESTRING = 5 MULTIPOLYGON = 6 GEOMETRYCOLLECTION = 7
`ST_GEOMFROMTEXT(wkt)`	Returns a geometry from the given Well-Known text representation `wkt`. Note that this function is only compatible with constants.
`ST_INTERIORRINGN(geom, n)`	Returns the `n`-th interior LINESTRING ring of the POLYGON `geom`. If `geom` is not a POLYGON or the given `n` is out of range, a `null` is returned. The index begins at 1.
`ST_INTERSECTION(geom1, geom2)`	Returns the shared portion between given geometries `geom1` and `geom2`.
`ST_INTERSECTS(geom1, geom2)`	Returns `1` (true) if the given geometries, `geom1` and `geom2`, intersect in 2-D.
`ST_ISCLOSED(geom)`	Returns `1` (true) if the given geometry's (`geom`) start and end points coincide.
`ST_ISCOLLECTION(geom)`	Returns `1` (true) if `geom` is a collection, e.g., GEOMETRYCOLLECTION, MULTIPOINT, MULTILINESTRING, etc.
`ST_ISEMPTY(geom)`	Returns `1` (true) if `geom` is empty.
`ST_ISRING(geom)`	Returns `1` (true) if LINESTRING `geom` is both closed (per `ST_ISCLOSED`) and "simple" (per `ST_ISSIMPLE`). Returns `0` if `geom` is not a LINESTRING.
`ST_ISSIMPLE(geom)`	Returns `1` (true) if `geom` has no anomalous geometric points, e.g., self-intersection or self-tangency.
`ST_ISVALID(geom)`	Returns `1` (true) if `geom` (typically a [MULTI]POLYGON) is well formed. A POLYGON is valid if its rings do not cross and its boundary intersects only at POINTs (not along a line). The POLYGON must also not have dangling LINESTRINGs. A MULTIPOLYGON is valid if all of its elements are also valid and the interior rings of those elements do not intersect. Each element's boundaries may touch but only at POINTs (not along a line).
`ST_LENGTH(geom)`	Returns the 2-D length of the geometry (in degrees) if it is a LINESTRING or MULTILINESTRING. Returns `0` if another type of geometry, e.g., POINT, MULTIPOINT, etc.
`ST_LINEFROMMULTIPOINT(geom)`	Creates a LINESTRING from `geom` if it is a MULTIPOINT. Returns `null` if `geom` is not a MULTIPOINT.
`ST_MAKEENVELOPE(xmin, ymin, xmax, ymax)`	Creates a rectangular POLYGON from the given min and max parameters.
`ST_MAKELINE(geom[, geom2, geom3])`	Creates a LINESTRING from `geom` if it is a MULTIPOINT. If `geom` is a POINT, there must be at least one other POINT to construct a LINESTRING. If `geom` is a LINESTRING, it must have at least two points. Returns `null` if `geom` is not a POINT, MULTIPOINT, or LINESTRING. Note: This function can be rather costly in terms of performance.
`ST_MAKEPOINT(x, y)`	Creates a POINT at the given coordinate. Note: This function can be rather costly in terms of performance.
`ST_MAKEPOLYGON(geom)`	Creates a POLYGON from `geom`. Inputs must be closed LINESTRINGs. Note: This function can be rather costly in terms of performance.
`ST_MAXX(geom)`	Returns the maximum x coordinate of a bounding box for the given `geom` geometry. This function works for 2-D and 3-D geometries.
`ST_MAXY(geom)`	Returns the maximum y coordinate of a bounding box for the given `geom` geometry. This function works for 2-D and 3-D geometries.
`ST_MAXZ(geom)`	Returns the maximum z coordinate of a bounding box for the given `geom` geometry. This function works for 2-D and 3-D geometries.
`ST_MINX(geom)`	Returns the minimum x coordinate of a bounding box for the given `geom` geometry. This function works for 2-D and 3-D geometries.
`ST_MINY(geom)`	Returns the minimum y coordinate of a bounding box for the given `geom` geometry. This function works for 2-D and 3-D geometries.
`ST_MINZ(geom)`	Returns the minimum z coordinate of a bounding box for the given `geom` geometry. This function works for 2-D and 3-D geometries.
`ST_MULTI(geom)`	Returns `geom` as a MULTI- geometry, e.g., a POINT would return a MULTIPOINT.
`ST_MULTIPLERINGBUFFERS(geom, distance, outside)`	Creates multiple buffers at specified `distance` around the given `geom` geometry. Multiple distances are specified as comma-separated values in an array, e.g., `[10,20,30]`. Valid values for `outside` are: `FULL` -- indicates that buffers will overlap or cover the given `geom` geometry. This is the default. `OUTSIDE_ONLY` -- indicates that buffers will be rings around the given `geom` geometry.
`ST_NORMALIZE(geom)`	Returns `geom` in its normalized (canonical) form, which may rearrange the points in lexicographical order.
`ST_NPOINTS(geom)`	Returns the number of points (vertices) in `geom`.
`ST_NUMGEOMETRIES(geom)`	If `geom` is a collection or MULTI- geometry, returns the number of geometries. If `geom` is a single geometry, returns 1.
`ST_NUMINTERIORRINGS(geom)`	Returns the number of interior rings if `geom` is a POLYGON. Returns `null` if `geom` is anything else.
`ST_NUMPOINTS(geom)`	Returns the number of points in the `geom` LINESTRING. Returns `null` if `geom` is not a LINESTRING.
`ST_OVERLAPS(geom1, geom2)`	Returns `1` (true) if given geometries `geom1` and `geom2` share space.
`ST_POINT(x, y)`	Returns a POINT with the given `x` and `y` coordinates.
`ST_POINTN(geom, n)`	Returns the `n`-th point in LINESTRING `geom`. Negative values are valid, but note that they are counted backwards from the end of `geom`. A `null` is returned if `geom` is not a LINESTRING.
`ST_POINTS(geom)`	Returns a MULTIPOINT containing all of the coordinates of `geom`.
`ST_REMOVEPOINT(geom, offset)`	Remove a point from LINESTRING `geom`. Index starts at 0, but you can use `offset` to make point selection easier.
`ST_REMOVEREPEATEDPOINTS(geom, tolerance)`	Removes points from `geom` if the point's vertices are greater than or equal to the `tolerance` of the previous point in the geometry's list. If `geom` is not a MULTIPOINT, MULTILINESTRING, or a MULTIPOLYGON, no points will be removed.
`ST_REVERSE(geom)`	Return the geometry with its coordinate order reversed.
`ST_SCALE(geom, x, y)`	Scales `geom` by multiplying its respective vertices by the given `x` and `y` values. This function also supports scaling `geom` using another geometry object, e.g., `ST_SCALE('POINT(3 4)', 'POINT(5 6)')` would return `POINT(15 24)`. If specifying `x` and `y` for scale, note that the default value is `0`, e.g., `ST_SCALE('POINT(1 3)', 4)` would return `POINT(4 0)`.
`ST_SETPOINT(geom1, position, geom2)`	Replace a point of LINESTRING `geom1` with POINT `geom2` at `position` (base 0). Negative values are valid, but note that they are counted backwards from the end of `geom`.
`ST_SHAREDPATH(geom1, geom2)`	Returns a collection containing paths shared by `geom1` and `geom2`.
`ST_SNAP(geom1, geom2, tolerance)`	Snaps `geom1` to `geom2` within the given `tolerance`. If the `tolerance` causes `geom1` to not snap, the geometries will be returned unchanged.
`ST_SPLIT(geom1, geom2)`	Returns a collection of geometries resulting from the split between `geom1` and `geom2` geometries.
`ST_STARTPOINT(geom)`	Returns the first point of LINESTRING `geom` as a POINT. Returns `null` if `geom` is not a LINESTRING.
`ST_SYMDIFFERENCE(geom1, geom2)`	Returns a geometry that represents the portions of `geom1` and `geom2` geometries that do not intersect.
`ST_TOUCHES(geom1, geom2)`	Returns `1` (true) if the given geometries, `geom1` and `geom2`, have at least one point in common but their interiors do not intersect.
`ST_TRANSLATE(geom, deltax, deltay)`	Translate `geom` by given offsets `deltax` and `deltay`. A z-coordinate offset can be applied using `deltaz`.
`ST_UNION(geom1, geom2)`	Returns a geometry that represents the point set union of the two given geometries, `geom1` and `geom2`.
`ST_UNIONCOLLECTION(geom)`	Returns a geometry that represents the point set union of a single given geometry `geom`.
`ST_UPDATE(geom1, geom2)`	Returns a geometry that is `geom1` geometry updated by `geom2` geometry
`ST_WITHIN(geom1, geom2)`	Returns `1` (true) if the `geom1` geometry is inside the `geom2` geometry. Note that as long as at least one point is inside of `geom2`, `geom1` is considered within `geom2` even if the rest of the `geom1` lies along the boundary of `geom2`
`ST_X(geom)`	Returns the X coordinate of the POINT `geom`; if the coordinate is not available, `null` is returned. `geom` must be a POINT.
`ST_Y(geom)`	Returns the Y coordinate of the POINT `geom`; if the coordinate is not available, `null` is returned. `geom` must be a POINT.

Geospatial Aggregation Functions¶

Function	Details
`ST_DISSOLVE(geom)`	Dissolves all geometries within a given set into a single geometry. Note that the resulting single geometry can still be a group of noncontiguous geometries but represented as a single group.