Connectors > MS SQL Server

There are two categories of objects that are interpreted as geometries in MS SQL Server:

Geometry	Geography
Compliant with the ST_GEOMETRY standard	Compliant with the ST_GEOMETRY standard
Accessible as WKT	Accessible as WKT
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 MS SQL 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 MS SQL Server and other data sources which similarly differentiate spatial data.

Geometry Types

Here is how MS SQL geometry and geography subtypes 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)
GEOMETRYCOLLECTION	Collection of any of the above	GeometryCollection (+ DTS corrections)

Z and M modifiers (e.g. POINT Z) are supported for all geometry types (except GEOMETRYCOLLECTION where they are not applicable), but the M values are always ignored and processing geometries with Z values has certain limitations.