Class SpatialCovers
- Namespace
- YndigoBlue.Velocity.Functions
- Assembly
- YndigoBlue.Velocity.dll
Represents the ST_Covers spatial predicate function that tests if one geometry completely covers another.
public class SpatialCovers : Function, IElement, ICheckItem, IDefaultItem, IFilterItem- Inheritance
-
SpatialCovers
- Implements
Remarks
Warning
Spatial functions are not available in the Community Edition of Velocity. They require the Full Edition.
The ST_Covers function returns true if every point of geometry B is a point of geometry A (interior or boundary). This is similar to ST_Contains but less strict regarding boundaries - a geometry covers another if no point of the second geometry lies outside the first. According to the DE-9IM model, this is useful for cases where boundary touching is acceptable. The inverse operation is ST_CoveredBy. Commonly used for containment queries where exact interior containment is not required. OGC-compliant.
Return Type: Boolean (true/false).
Key Difference from ST_Contains: ST_Contains requires B to be in A's interior (not touching boundary). ST_Covers allows B to touch A's boundary and still return TRUE.
| Relationship | ST_Covers vs ST_Contains |
|---|---|
| B fully inside A (interior) | Both TRUE |
| B on A's boundary edge | Covers: TRUE, Contains: FALSE |
| Point on polygon edge | Covers: TRUE, Contains: FALSE |
| B extends outside A | Both FALSE |
Constructors
- SpatialCovers(Geometry, Column)
Initializes a new instance of ST_Covers with a geometry literal and column.
- SpatialCovers(Geometry, Function)
Initializes a new instance of ST_Covers with a Geometry literal and function result for function chaining.
- SpatialCovers(Column, Geometry)
Initializes a new instance of ST_Covers with a column and geometry literal.
- SpatialCovers(Column, Column)
Initializes a new instance of ST_Covers with two columns for spatial joins.
- SpatialCovers(Column, Function)
Initializes a new instance of ST_Covers with a column and function result for function chaining.
- SpatialCovers(Column, Geography)
Initializes a new instance of ST_Covers with a column and geography literal.
- SpatialCovers(Function, Geometry)
Initializes a new instance of ST_Covers with a function result and Geometry literal for function chaining.
- SpatialCovers(Function, Column)
Initializes a new instance of ST_Covers with a function result and column for function chaining.
- SpatialCovers(Function, Function)
Initializes a new instance of ST_Covers with two function results for function chaining.
- SpatialCovers(Function, Geography)
Initializes a new instance of ST_Covers with a function result and Geography literal for function chaining.
- SpatialCovers(Geography, Column)
Initializes a new instance of ST_Covers with a geography literal and column.
- SpatialCovers(Geography, Function)
Initializes a new instance of ST_Covers with a Geography literal and function result for function chaining.