# 14.19. Geospatial Functions

Presto Geospatial functions support the SQL/MM specification. They are compliant with the Open Geospatial Consortium’s (OGC) OpenGIS Specifications. As such, many Presto Geospatial functions require, or more accurately, assume that geometries that are operated on are both simple and valid. For example, it does not make sense to calculate the area of a polygon that has a hole defined outside of the polygon, or to construct a polygon from a non-simple boundary line.

Presto Geospatial functions support the Well-Known Text (WKT) form of spatial objects:

• `POINT (0 0)`
• `LINESTRING (0 0, 1 1, 1 2)`
• `POLYGON ((0 0, 4 0, 4 4, 0 4, 0 0), (1 1, 2 1, 2 2, 1 2, 1 1))`
• `MULTIPOINT (0 0, 1 2)`
• `MULTILINESTRING ((0 0, 1 1, 1 2), (2 3, 3 2, 5 4))`
• `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)))`
• `GEOMETRYCOLLECTION (POINT(2 3), LINESTRING (2 3, 3 4))`

## Constructors

`ST_Point`(double, double) → Point

Returns a geometry type point object with the given coordinate values.

`ST_LineFromText`(varchar) → LineString

Returns a geometry type linestring object from WKT representation.

`ST_Polygon`(varchar) → Polygon

Returns a geometry type polygon object 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. For empty geometries, `ST_AsText(ST_LineFromText('LINESTRING EMPTY'))` will produce `'MULTILINESTRING EMPTY'` and `ST_AsText(ST_Polygon('POLYGON EMPTY'))` will produce `'MULTIPOLYGON EMPTY'`.

## Relationship Tests

`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.

`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 give geometries do not spatially intersect – if they do not share any space together.

`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 don 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 first geometry is spatially related to second geometry.

`ST_Touches`(Geometry, 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 first geometry is completely inside second geometry.

## Operations

`ST_Boundary`(Geometry) → Geometry

Returns the closure of the combinatorial boundary of this geometry.

`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.

## Accessors

`ST_Area`(Geometry) → double

Returns the area of a polygon using Euclidean measurement on a two dimensional plane (based on spatial ref) in projected units.

`ST_Centroid`(Geometry) → Geometry

Returns the point value that is the mathematical centroid of a geometry.

`ST_CoordDim`(Geometry) → bigint

Return the coordinate dimension of the geometry.

`ST_Dimension`(Geometry) → bigint

Returns the inherent dimension of this geometry object, which must be less than or equal to the coordinate dimension.

`ST_Distance`(Geometry, Geometry) → double

Returns the 2-dimensional cartesian minimum distance (based on spatial ref) between two geometries in projected units.

`ST_IsClosed`(Geometry) → boolean

Returns `true` if the linestring’s start and end points are coincident.

`ST_IsEmpty`(Geometry) → boolean

Returns `true` if this Geometry is an empty geometrycollection, polygon, point etc.

`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 linestring or multi-linestring using Euclidean measurement on a two dimensional plane (based on spatial ref) in projected units.

`ST_XMax`(Geometry) → double

Returns X maxima of a bounding box of a geometry.

`ST_YMax`(Geometry) → double

Returns Y maxima of a bounding box of a geometry.

`ST_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 LineString geometry as a Point.

`ST_EndPoint`(Geometry) → point

Returns the last point of a LineString geometry as a Point.

`ST_X`(Point) → double

Return the X coordinate of the point.

`ST_Y`(Point) → double

Return the Y coordinate of the point.

`ST_NumPoints`(Geometry) → bigint

Returns the number of points in a geometry. This is an extension to the SQL/MM `ST_NumPoints` function which only applies to point and linestring.

`ST_NumInteriorRing`(Geometry) → bigint

Returns the cardinality of the collection of interior rings of a polygon.

## Bing Tiles

These functions convert between geometries and Bing tiles.

`bing_tile`(x, y, zoom_level) → BingTile

Creates a Bing tile object from XY coordinates and a zoom level. Zoom levels from 1 to 23 are supported.

`bing_tile`(quadKey) → BingTile

Creates a Bing tile object from a quadkey.

`bing_tile_at`(latitude, longitude, zoom_level) → BingTile

Returns a Bing tile at a given zoom level containing a point at a given latitude and longitude. Latitude must be within `[-85.05112878, 85.05112878]` range. Longitude must be within `[-180, 180]` range. Zoom levels from 1 to 23 are supported.

`bing_tile_coordinates`(tile) → row<x, y>

Returns the XY coordinates of a given Bing tile.

`bing_tile_polygon`(tile) → Geometry

Returns the polygon representation of a given Bing tile.

`bing_tile_quadkey`(tile) → varchar

Returns the quadkey of a given Bing tile.

`bing_tile_zoom_level`(tile) → tinyint

Returns the zoom level of a given Bing tile.

`geometry_to_bing_tiles`(geometry, zoom_level) → array<BingTile>

Returns the minimum set of Bing tiles that fully covers a given geometry at a given zoom level. Zoom levels from 1 to 23 are supported.