Connectors > PostgreSQL

PostgreSQL can include two separate geometry sets: native (simple) geometries and PostGIS (ST) geometries.

DTS maps both sets to DTSGeoJson.

Native Geometry Types

PostgreSQL Geometry Type	Interpretation	GeoJson Geometry Type
point	Single point	Point
lseg	Line segment	LineString
path	Sequence of connected line segments - can be open [] or closed ()	LineString or Polygon
box	Rectangle	Polygon + DTS Correction
box2d	Rectangle	Polygon + DTS Correction
polygon	Polygon	Polygon
circle	Circle	Polygon + DTS Correction

The infinite "line" type is not supported

The 3-dimensional "box3d" type is not supported

Native geometry types can only be used as function inputs when they are direct arguments. Please see Limitations for details.

PostGIS Geometry Types

There are two categories of objects that are interpreted as geometries in PostgreSQL:

Geometry	Geography
Compliant with the ST_GEOMETRY standard	Compliant with the ST_GEOMETRY standard
Accessible as WKB	Accessible as WKB
Strictly euclidean	Strictly geodetic
Coordinates represent (x, y) or (x, y, z)	Coordinates represent (lon, lat) or (lon, lat, elv)
If specified, coordinate system must be in length units	If specified, coordinate system must be in degrees

The DTS PostgreSQL Connector transforms both categories to DTSGeoJson for transfer, but keeps track of the them as different internal types (DTS_GEOMETRY, DTS_GEOGRAPHY) in order to correctly interact with PostgreSQL and other data sources which similarly differentiate spatial data.

Here is how PostGIS geometry and geography types map to GeoJson geometry types.

ST Subtype	Interpretation	GeoJson Geometry Type
POINT	Single point	Point
MULTIPOINT	Multiple points	MultiPoint
LINESTRING	Sequence of straight lines without gaps	LineString
CIRCULARSTRING	Sequence of circle arcs without gaps	LineString + DTS corrections
MULTILINESTRING	Multiple LINESTRINGs (not necessarily connected)	MultiLineString
COMPOUNDCURVE	Sequence of connected LINESTRINGs and CIRCULARLINESTRINGs	MultiLineString + DTS corrections
POLYGON	Polygon (with or without holes)	Polygon
CURVEPOLYGON	Polygon whose boundaries can contain circle arcs	Polygon + DTS corrections
MULTIPOLYGON	Multiple POLYGONs	MultiPolygon (+ DTS corrections)

Only the 2-dimensional variants of these geometries are supported at present.

GEOMETRYCOLLECTIONs are not currently supported.