Editing Geography Markup Language (section)

===Features===

GML defines ''features'' distinct from ''geometry objects''. A ''feature'' is an application object that represents a physical entity, e.g. a building, a river, or a person. A ''feature'' may or may not have geometric aspects. A ''geometry object'' defines a location or region instead of a physical entity, and hence is different from a ''feature''.

In GML, a ''feature'' can have various geometry properties that describe geometric aspects or characteristics of the feature (e.g. the feature's ''Point'' or ''Extent'' properties).
GML also provides the ability for ''features'' to share a geometry property with one another by using a ''remote property reference'' on the shared geometry property. Remote properties are a general feature of GML borrowed from RDF. An ''xlink:href'' attribute on a GML geometry property means that the value of the property is the resource referenced in the link.

For example, a ''Building'' feature in a particular GML application schema might have a position given by the primitive GML geometry object type ''Point''.  However, the ''Building'' is a separate entity from the ''Point'' that defines its position.  In addition, a ''feature'' may have several geometry properties (or none at all), for example an ''extent'' and a ''position''.