Class SpatialSymDifference
- Namespace
- YndigoBlue.Velocity.Functions
- Assembly
- YndigoBlue.Velocity.dll
Represents the ST_SymDifference spatial analysis function that computes the symmetric difference of two geometries.
public class SpatialSymDifference : Function, IElement, ICheckItem, IDefaultItem, IFilterItem- Inheritance
-
SpatialSymDifference
- Implements
Remarks
Warning
Spatial functions are not available in the Community Edition of Velocity. They require the Full Edition.
The ST_SymDifference function returns a geometry representing the symmetric difference (XOR) of two spatial objects. This is the set of points that are in either geometry but not in both - essentially the union minus the intersection. The result contains only the non-overlapping portions of the two geometries. Useful for finding areas of exclusive coverage, detecting differences between versions of spatial data, or change detection analysis. OGC-compliant.
Return Type: Geometry (portions of A and B that do not overlap).
Formula: SymDifference(A, B) = Union(A, B) - Intersection(A, B) = (A - B) + (B - A)
| Relationship | ST_SymDifference(A, B) Result |
|---|---|
| A and B overlap partially | Two regions: A-only and B-only portions |
| A and B are disjoint | MultiPolygon containing both A and B |
| A equals B | EMPTY geometry (complete overlap) |
| B fully contains A | B with A-shaped hole |
Constructors
- SpatialSymDifference(Geometry, Column)
Initializes a new instance of ST_SymDifference with a geometry literal and column.
- SpatialSymDifference(Geometry, Function)
Initializes a new instance of ST_SymDifference with a Geometry literal and function result for function chaining.
- SpatialSymDifference(Column, Geometry)
Initializes a new instance of ST_SymDifference with a column and geometry literal.
- SpatialSymDifference(Column, Column)
Initializes a new instance of ST_SymDifference with two columns for spatial joins.
- SpatialSymDifference(Column, Function)
Initializes a new instance of ST_SymDifference with a column and function result for function chaining.
- SpatialSymDifference(Column, Geography)
Initializes a new instance of ST_SymDifference with a column and geography literal.
- SpatialSymDifference(Function, Geometry)
Initializes a new instance of ST_SymDifference with a function result and Geometry literal for function chaining.
- SpatialSymDifference(Function, Column)
Initializes a new instance of ST_SymDifference with a function result and column for function chaining.
- SpatialSymDifference(Function, Function)
Initializes a new instance of ST_SymDifference with two function results for function chaining.
- SpatialSymDifference(Function, Geography)
Initializes a new instance of ST_SymDifference with a function result and Geography literal for function chaining.
- SpatialSymDifference(Geography, Column)
Initializes a new instance of ST_SymDifference with a geography literal and column.
- SpatialSymDifference(Geography, Function)
Initializes a new instance of ST_SymDifference with a Geography literal and function result for function chaining.