Process Feature Plugin ---------------------- The ``gt-process-feature`` plugin gathers up a number of high quality processes for working with vector information. **Maven**:: org.geotools gt-process-feature ${geotools.version} Transform ^^^^^^^^^ Transform a feature collection using a series of expressions to define each attribute. The definition of the output feature type can be provided as a Definition data structure or using a simple string format: .. literalinclude:: /../src/main/java/org/geotools/process/FeatureProcessExamples.java :language: java :start-after: // transform start :end-before: // transform end This is a very flexible process which can be used to: * Change the order of attributes - resulting in a new feature type:: INPUT Schema DEFINITION OUTPUT Schema the_geom: Polygon the_geom the_geom: Polygon name: String id id: Long id: Long name name: String description: String description description: String * Rename or remove attributes - resulting in a new feature type:: INPUT Schema DEFINITION OUTPUT Schema the_geom: Polygon the_geom the_geom: Polygon name: String id_code=id id_code: Long id: Long summary=description summary: String description: String * Process geometry - using functions like ``the_geom=simplify( the_geom, 2.0 )`` or ``the_geom=centriod( the_geom )``:: INPUT Schema DEFINITION OUTPUT Schema the_geom: Polygon the_geom=centriod(the_geom) the_geom: Point name: String name name: String id: Long id id: Long description: String description description: String * Generate additional attributes using the form: ``area=area( the_geom )``:: INPUT Schema DEFINITION OUTPUT Schema the_geom: Polygon the_geom=centriod(the_geom) the_geom: Point name: String name name: String id: Long id id: Long description: String description description: String area=area( the_geom) area: Double text=concatenate(name,'-',id) text: String Group candidate selection ^^^^^^^^^^^^^^^^^^^^^^^^^ Filters a FeatureCollection according to the aggregate operation chosen (MIN or MAX) and the groups defined through attribute names. Given a feature collection, groups according to the defined grouping attributes, and returns the feature having the MIN or MAX value for the chosen attribute. One feature will be chosen for each group. This vector process accepts four parameters: * ``data``: the data on which perform the computation. * ``aggregation``: the type of operation required to filter data (MIN or MAX). * ``operationAttribute``: the xpath to the attribute whose value will be used to perform the MIN or MAX operation. * ``groupingAttributes``: a lists of xpath pointing to the attirbutes defining the features' groups for which perform the filtering process. The process ensures a consistent results only if the FeatureCollection has already been sorted by the feature's attributes passed as the ``groupingAttributes`` parameter.