Class SpatialExteriorRing

Namespace

YndigoBlue.Velocity.Functions

Assembly

YndigoBlue.Velocity.dll

Represents the ST_ExteriorRing spatial accessor function that returns the exterior ring of a polygon geometry.

public class SpatialExteriorRing : Function, IElement, ICheckItem, IDefaultItem, IFilterItem

Inheritance

object

Function

SpatialExteriorRing

Implements

IElement

ICheckItem

IDefaultItem

IFilterItem

Remarks

Warning

Spatial functions are not available in the Community Edition of Velocity. They require the Full Edition.

The ST_ExteriorRing function returns a linestring representing the outer boundary ring of a polygon geometry. For multi-polygons or non-polygon geometries, behavior varies by database implementation (may return null or the exterior ring of the first polygon). The exterior ring defines the outer boundary, while interior rings (holes) are accessed separately. For Geometry types in planar coordinate systems, this is useful for extracting polygon boundaries, topology analysis, or converting polygons to linear features. OGC-compliant.

Return Type: LineString (closed ring representing the outer boundary).

Input	ST_ExteriorRing Result
Simple polygon	Outer boundary as LineString
Polygon with holes	Outer boundary only (holes not included)
Point, LineString	NULL

Constructors

SpatialExteriorRing(Geometry)

Initializes a new instance of ST_ExteriorRing with a polygon geometry literal.

SpatialExteriorRing(Column)

Initializes a new instance of ST_ExteriorRing with a polygon geometry column.

SpatialExteriorRing(Function)

Initializes a new instance of ST_ExteriorRing for a function result.

SpatialExteriorRing(Geography)

Initializes a new instance of ST_ExteriorRing with a polygon geography literal.