Functions which operate on Geometric Values.

Information

Most of the geometric functions can be passed either a string containing Well Known Text 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 WKT 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. 

For more information on this topic see: Well Known Text

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 non-geometry functions toString() must be called.

Functions

The following function perform geometric operations: