Geospatial concept

Geospatial functions support the geometries in the Well-Known Text (WKT) format.

Table 1. Geometry format
Geometry Well-maid text (WKT) Format
Point POINT (0 0)
Line string LINESTRING (0 0, 1 1, 1 2)
Polygon Polygon
Multi-point MULTIPOINT (0 0, 1 2)
Multi-line string MULTILINESTRING ((0 0, 1 1, 1 2), (2 3, 3 2, 5 4))
Multi-polygon MULTIPOLYGON (((0 0, 4 0, 4 4, 0 4, 0 0), (1 1, 2 1, 2 2, 1 2, 1 1)), ((-1 -1, -1 -2, -2 -2, -2 -1, -1 -1)))
Geometry collection GEOMETRYCOLLECTION (POINT(2 3), LINESTRING (2 3, 3 4))

Constructors

Table 2. Constructors Description
Function Description 
ST_Point(double, double) → Point Returns a geometry type point with the given coordinate values.
ST_LineFromText(varchar) → LineString Returns a geometry type line string from WKT representation.
ST_Polygon(varchar) → Polygon Returns a geometry type polygon from WKT representation.
ST_GeometryFromText(varchar) → Geometry Returns a geometry type object from WKT representation.
ST_AsText(Geometry) → varchar Returns the WKT representation of the geometry.

Operations

Function Description
ST_Boundary(Geometry) → Geometry Returns the closure of the combinatorial boundary of this geometry.
ST_Buffer(Geometry, distance) → Geometry Returns the geometry that represents all points whose distance from the specified geometry is less than or equal to the specified distance.
ST_Difference(Geometry, Geometry) → Geometry Returns the geometry value that represents the point set difference of the given geometries.
ST_Envelope(Geometry) → Geometry Returns the bounding rectangular polygon of a geometry.
ST_ExteriorRing(Geometry) → Geometry Returns a line string representing the exterior ring of the input polygon.
ST_Intersection(Geometry, Geometry) → Geometry Returns the geometry value that represents the point set intersection of two geometries.
ST_SymDifference(Geometry, Geometry) → Geometry Returns the geometry value that represents the point set  symmetric difference of two geometries.

Relationship tests

Function Description
ST_Contains(Geometry, Geometry) → boolean Returns true if and only if no points of the second geometry lie in the exterior of the first geometry, and at least one point of the interior of the first geometry lies in the interior of the second geometry.  Returns false if the two geometries at least share an interior point.
ST_Crosses(Geometry, Geometry) → boolean Returns true if the supplied geometries have some, but not all, interior points in common.
ST_Disjoint(Geometry, Geometry) → boolean Returns true if the given geometries do not spatially intersect.
ST_Equals(Geometry, Geometry) → boolean Returns true if the given geometries represent the same geometry.
ST_Intersects(Geometry, Geometry) → boolean Returns true if the given geometries spatially intersect in two dimensions (share any portion of space) and false if they do not (they are disjoint).
ST_Overlaps(Geometry, Geometry) → boolean Returns true if the given geometries share space, are of the same dimension, but are not completely contained by each other.
ST_Relate(Geometry, Geometry) → boolean Returns true if the first geometry is spatially related to the second geometry.
ST_Touches(Geometry, Geometry) → boolean Geometry) → boolean Returns true if the given geometries have at least one point in common, but their interiors do not intersect.
ST_Within(Geometry, Geometry) → boolean Returns true if the first geometry is completely inside the second geometry.  Returns false if the two geometries have at least one point in common.

Accessors

Function Description
ST_Area(Geometry) → double Returns the area of a polygon using Euclidean measurement on a two dimensional plane in projected units.
ST_Centroid(Geometry) → Geometry Returns the point value that is the mathematical centroid of a geometry.
ST_CoordDim(Geometry) → bigint Returns the coordinate dimension of the geometry.
ST_Dimension(Geometry) → bigint Returns the inherent dimension of this geometry, which must be less than or equal to the coordinate dimension.
ST_Distance(Geometry, Geometry) → double Returns the minimum distance between two geometries.
ST_IsClosed(Geometry) → boolean Returns true if the start and end points of the line string are coincident.
ST_IsEmpty(Geometry) → boolean Returns true if this geometry is an empty geometry collection, polygon, or point.
ST_IsRing(Geometry) → boolean Returns true if and only if the line is closed and simple.
ST_Length(Geometry) → double Returns the length of a line string or multi-line string  using Euclidean measurement on a two  dimensional plane (based on spatial ref) in projected units.
ST_XMax(Geometry) → double  Returns Y maxima of a bounding box of a geometry.
ST_YMax(Geometry) → double Returns Y maxima of a bounding box of a geometry.
T_XMin(Geometry) → double Returns X minima of a bounding box of a geometry.
ST_YMin(Geometry) → double Returns Y minima of a bounding box of a geometry.
ST_StartPoint(Geometry) → point  Returns the first point of a line string geometry.
ST_EndPoint(Geometry) → point Returns the last point of a line string geometry.
ST_X(Point) → double Returns the X coordinate of the point.
ST_Y(Point) → double Returns the Y coordinate of the point.
ST_NumPoints(Geometry) → bigint Returns the number of points in a geometry.
ST_NumInteriorRing(Geometry) → bigint Returns the number of interior rings of a polygon.