Project: QGIS
Version: 2.14.0
Geometry generator symbols allow using the expression engine to modify the geometry before rendering or even creating new geometries while rendering based on feature attributes.
This can be used to use all kinds of spatial operators like buffer, translate, intersect or extrude with parameters based on attributes only for the rendering without actually modifying the data in the source.
Examples
Translate a geometry
Used for the roof of the 2.5D renderer
translate( $geometry, 10, 10 )
Fill style for polygon border
This generates a polygon which represents the outline of the original polygon (Example image)
difference( buffer( $geometry , 250 ), buffer( $geometry, -250 ) )
Different symbol layers can contain different geometry generators, this allows displaying different versions of a geometry at the same time. The 2.5D renderer serves as an example.
This feature was funded by Regional Council of Picardy, ADUGA, Ville de Nyon, Wetu GIT cc
This feature was developed by Matthias Kuhn, OPENGIS.ch