Geometry (Variable type)

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Properties specific to Geometry variables
Functions that use the Geometry type

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Geometry (Variable type)

In french: Geometry

The Geometry type can be used to store any type of geometry: point, polygon, etc.

This means that any WLanguage function that can return a point or polygon depending on its parameters, can have a variable of type Geometry as return value.

Once declared, Geometry variables are empty until a value is assigned to them.

Note: For more details on the declaration of this type of variable and the use of WLanguage properties, see Declaring a variable.

Example

// Example 1: Get a point without verification
f is Geometry()
// Get geometry
f = GetPoint() // GetPoint is a procedure used to get a point
p is Point2D = f

// Example 2: Check type of geometry to make sure a point is retrieved before attempting conversion
f is Geometry 
// Get geometry ...
// Check geometry
IF f.Type = gtPoint2D THEN
   my2DPoint is Point2D
   my2DPoint = f
   //...
END

// Example 3: The type of a geometry can be changed
point is Point2D
linestring is Linestring2D
f is Geometry // Geometry is empty and can take any type of geometry
f = point // Geometry now contains a Point2D object.
f = linestring // Geometry now contains a Linestring2D object.

// Example 4: Get a geographic polygon without verification
// No need to declare an intermediate geometry 
// Directly convert the result of a function
f = GetGeometry() // GetGeometry is a procedure used to get a geometry
IF f.Type = gtPolygonGeo THEN
   polygon is PolygonGeo
   polygon = f
   // ...
END

// Example 5: If the type of geometry retrieved is unknown,
// different code can be executed according to the type of geometry
UnknownGeometry is Geometry
UnknownGeometry = GetUnknownGeometry() 
// GetUnknownGeometry is a procedure used to get a geometry
SWITCH UnknownGeometry.Type 
	CASE gtPoint2D:
	       // ...
	CASE gtLinestring2D:
	       // ...
	CASE gtPolygon2D:
	       // ...
	OTHER CASE:
	       // ...
END

Properties

Properties specific to Geometry variables

The following properties can be used to manipulate a variable of type Geometry:

Property name	Type used	Effect

Type	Integer constant	Type of the current geometry: gtInvalid: Invalid type. Note: Until version 2024 Update 2, this constant was named stInvalid. gtGeometryCollection: Collection of geometries. Note: Until version 2024 Update 2, this constant was named stShapeCollection. gtMultiPoint2D: Collection of 2D points. Note: Until version 2024 Update 2, this constant was named stMultiPoint2D. gtMultiPointGeo: Collection of geographic points. Note: Until version 2024 Update 2, this constant was named stMultiPointGeo. gtMultiPolygon2D: Collection of 2D polygons. Note: Until version 2024 Update 2, this constant was named stMultiPolygon2D. gtMultiPolygonGeo: Collection of geographic polygons. Note: Until version 2024 Update 2, this constant was named stMultiPolygonGeo. gtMultiLinestring2D: Collection of 2D multilinestrings. Note: Until version 2024 Update 2, this constant was named stMultiLinestring2D. gtMultiLinestringGeo: Collection of geographic linestrings. Note: Until version 2024 Update 2, this constant was named stMultiLinestringGeo. tgPoint2D: 2-dimensional point, defined by X and Y coordinates on a Cartesian plane. Note: Until version 2024 Update 2, this constant was named stPoint2D. gtPointGeo: Geographic point, defined by latitude and longitude. Note: Until version 2024 Update 2, this constant was named stPointGeo. tgPolygone2D: Collection of straight consecutive segments that form a polygon. Note: Until version 2024 Update 2, this constant was named stPolygon2D. gtPolygonGeo: Collection of consecutive curved segments that form a polygon (the curvature of these segments respects the Earth's curvature). Note: Until version 2024 Update 2, this constant was named stPolygonGeo. gtLinestring2D: Set of consecutive straight segments. Note: Until version 2024 Update 2, this constant was named stLinestring2D. gtLinestringGeo: Collection of consecutive curved segments (the curvature of these segments respects the Earth's curvature). Note: Until version 2024 Update 2, this constant was named stLinestringGeo. This property is available in read-only.

Remarks

Functions that use the Geometry type

The following functions use Geometry variables:


GeometryArea	Calculates the area of a given geometry.
GeometryContain	Determines if geometry A contains geometry B.
GeometryConvexHull	Calculates the convex hull of the specified geometry.
GeometryCorrect	Returns a corrected version of the specified geometry.
GeometryCover	Determines if geometry A covers geometry B.
GeometryCoveredBy	Determines if every point of geometry A lies inside or on the boundary of geometry B.
GeometryCross	Compares two geometries and determines if their intersection spatially crosses.
GeometryDeserializeWKT2D	Builds a 2D geometry from a Well-Known Text (WKT) representation.
GeometryDeserializeWKTGeo	Builds a geometry in geographic coordinates from a Well-Known Text (WKT) representation.
GeometryDifference	Returns a geometry representing the difference between two geometries.
GeometryDisjoint	Determines whether two geometries are disjoint, i.e. whether their intersection is empty.
GeometryDistance	Calculates the distance between two geometries.
GeometryEqual	Determines whether two geometries are spatially equal, i.e. whether the first geometry is included in the second, and vice versa.
GeometryIntersect	Checks whether two geometries have a non-empty intersection.
GeometryIntersection	Returns a geometry representing the intersection of two geometries.
GeometryIsValid	Checks whether the specified geometry is valid according to the OGC rules.
GeometryLength	Calculates the length of a given geometry.
GeometryOverlap	Determines whether two geometries overlap.
GeometryPerimeter	Calculates the perimeter of a given geometry (polygon or multipolygon).
GeometrySerializeDSV	Serializes a geometry using the specified DSV format.
GeometrySerializeWKT	Serializes a geometry using the Well-Known Text (WKT) format.
GeometrySymmetricDifference	Calculates the symmetric difference between two geometries.
GeometryTouch	Determines whether two geometries touch.
GeometryUnion	Returns a geometry corresponding to the union of two geometries.
GeometryWithin	Determines whether geometry A is completely within geometry B (i.e., geometry B completely contains geometry A).