DefaultGeographySRID (aka 4326) is the GPS lat/lng we all know and love.

DefaultGeometrySRID is the same as being unknown.

MShapeTypeFlag indicates a M dimension on the ShapeType.

Geometry can contain any type.

GeometryCollection can contain a list of any above type except for Geometry.

UnknownSRID is the default SRID if none is provided.

ZShapeTypeFlag indicates a Z dimension on the ShapeType.

BoundingBox represents the bounding box of a Geospatial type.

SpatialObject represents a serialization of a Geospatial type.

EWKB is the Extended Well Known Bytes form of a spatial object.

EWKT is the Extended Well Known Text form of a spatial object.

ShapeType is the type of a spatial shape.

SpatialObjectType represents the type of the SpatialObject.

SRID is a Spatial Reference Identifer.

WKB is the Well Known Bytes form of a spatial object.

WKT is the Well Known Text form of a spatial object.