Class SpatialArea
- Namespace
- YndigoBlue.Velocity.Functions
- Assembly
- YndigoBlue.Velocity.dll
Represents the ST_Area spatial function that calculates the area of a polygon or multi-polygon geometry.
public class SpatialArea : Function, IElement, ICheckItem, IDefaultItem, IFilterItem- Inheritance
-
SpatialArea
- Implements
Remarks
Warning
Spatial functions are not available in the Community Edition of Velocity. They require the Full Edition.
The ST_Area function returns the area of a geometry. For Geometry types (planar), it calculates area in coordinate system units squared. For Geography types (spherical), it calculates area on the earth's surface, optionally in specified units. Returns 0 for non-areal geometries (points, lines). Useful for land area calculations, geographic analysis, and spatial statistics. OGC-compliant.
Geometry Mode (planar, returns square coordinate units):
| Shape | Area |
|---|---|
| PY0 (4°×4° square) | 16.0 |
| PY1 (0.5°×1° rectangle) | 0.5 |
| PY2 (1°×3° rectangle) | 3.0 |
| PY3 (triangle) | 0.25 |
| PY4 (2°×1.5° rectangle) | 3.0 |
| PT1, PT2 (points) | 0 |
| LN1 (linestring) | 0 |
Geography Mode (spherical, returns square meters by default):
| Shape | Area (m² default, km² with UnitOfMeasure) |
|---|---|
| PY0 | ~157,650,000,000 m² (~157,650 km²) |
| PY1 | ~4,900,000,000 m² (~4,900 km²) |
| PY2 | ~36,800,000,000 m² (~36,800 km²) |
| PY3 | ~3,100,000,000 m² (~3,100 km²) |
| PY4 | ~36,900,000,000 m² (~36,900 km²) |
| PT1, PT2, LN1 | 0 (non-areal geometries) |
Units of Measure: For Geography types, the default unit is square meters. Use the SpatialArea(Column, UnitOfMeasure) constructor with UnitOfMeasure to specify alternative units such as square kilometers, square miles, or hectares.
Constructors
- SpatialArea(Geometry)
Initializes a new instance of ST_Area for a geometry literal.
- SpatialArea(Column)
Initializes a new instance of ST_Area for a geometry column.
- SpatialArea(Column, UnitOfMeasure)
Initializes a new instance of ST_Area for a geography column with a unit of measure.
- SpatialArea(Function)
Initializes a new instance of ST_Area for a function result (e.g., from another spatial operation).
- SpatialArea(Function, UnitOfMeasure)
Initializes a new instance of ST_Area for a function result with a unit of measure.
- SpatialArea(Geography, UnitOfMeasure)
Initializes a new instance of ST_Area for a geography literal with a unit of measure.