Geospatial Objects

This article describes geospatial objects in Exasol.

Geospatial data is information that identifies geographic features, locations, and boundaries on Earth. By using geospatial data, you can store and analyze geographical information. In Exasol, geospatial data is stored as GEOMETRY objects that are defined through coordinates stored as strings, for example, 'POINT(2 5)'.

Geospatial Objects

The following types of geospatial objects can be defined in Exasol:

 

Constructor Description
GEOMETRY General abstraction of any geospatial object
POINT (X Y) Point within the two-dimensional area
LINESTRING (X Y, X Y,...) LineString that connects several two-dimensional Points
LINEARRING (X Y, X Y,...) A LineString whose start and end Points are identical
POLYGON ((X Y,...)[,(X Y,...),...]) Area defined by a linear ring and an optional list of holes within this area
GEOMETRYCOLLECTION (geometry,...) A collection of any geospatial objects
MULTIPOLYGON ((X Y,...),...) Set of Polygons
MULTILINESTRING ((X Y,...),...) Set of LineStrings
MULTIPOINT (X Y,...) Set of Points

To create an empty set of a geospatial object you can use the keyword EMPTY instead of numerical arguments. For example: POLYGON EMPTY.

Example

POINT(2 5)                -- PT
LINESTRING(11 1, 15 2, 15 10)        -- L
POLYGON((5 1, 5 5, 9 7, 10 1, 5 1),
(6 2, 6 3, 7 3, 7 2, 6 2))        -- PG


MULTIPOINT(0.1 1.4, 2.2 3, 1 6.4)
MULTILINESTRING((0 1, 2 3, 1 6), (4 4, 5 5))
MULTIPOLYGON(((0 0, 0 2, 2 2, 3 1, 0 0)),
((4 6, 8 9, 12 5, 4 6), (8 6, 9 6, 9 7, 8 7, 8 6)))
GEOMETRYCOLLECTION(POINT(2 5), LINESTRING(1 1, 15 2, 15 10))

Included geometry data types:

  • POINT - p
  • LINESTRING - ls
  • MULTILINESTRING - mls
  • POLYGON - pg
  • MULTIPOLYGON - mp
  • GEOMETRY - g
  • GEOMETRYCOLLECTION - gc
  • INTEGER - n

GEOMETRY columns can optionally have an SRID (spatial reference system identifier), which defines a reference coordinate system that acts as a constraint. For more information, see EXA_SPATIAL_REF_SYS