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Information

If passed a string the geometry functions will automatically convert the value into a Geometry object. Where Most of the geometric functions can be passed either a a string containing Well Known Text String format or a Geometry Object as described below.

Geometric Data Types

Well Known Text

Well known text (WKT) is a text mark up language for representing vector geometry objects. Most geometric functions accept a string containing well formed WKT syntax. These are known as WTK strings. For example, "POLYGON ((30 10, 40 40, 20 40, 10 20, 30 10))".

WKT is commonly generated and used by Geographic Information Systems (GIS) or geographical databases. 

Geometry

Many geometry functions return a "Geometry" object this is the internal optimised representation of the results which can be passed directly into other geometry functions.

Where the final result of an expression is a geometry object then this will automatically be converted into a String once evaluation is complete.

To convert a Geometry object into a Well Known Text* string, so that it can be passed to other attribute non-geometry functions , toString() must be called.Well-known text (WKT) is a text markup language for representing vector geometry objects

Functions

The following function perform geometric operations:

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