org.geotools.process.vector

Class PointStackerProcess

Object

PointStackerProcess

All Implemented Interfaces:

VectorProcess

public class PointStackerProcess
extends Object
implements VectorProcess

A Rendering Transformation process which aggregates features into a set of visually non-conflicting point features. The created points have attributes which provide the total number of points aggregated, as well as the number of unique point locations.

This is sometimes called "point clustering". The term stacking is used instead, since clustering has multiple meanings in geospatial processing - it is also used to mean identifying groups defined by point proximity.

The stacking is defined by specifying a grid to aggregate to. The grid cell size is specified in pixels relative to the requested output image size. This makes it more intuitive to pick an appropriate grid size, and ensures that the aggregation works at all zoom levels.

The output is a FeatureCollection containing the following attributes:

• geom - the point representing the cluster
• count - the total number of points in the cluster
• countunique - the number of unique point locations in the cluster

Note that as required by the Rendering Transformation API, the output has the CRS of the input data.

Author:

mdavis, Cosmin Cioranu (CozC)

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	PointStackerProcess.PreserveLocation

Field Summary

Fields

Modifier and Type	Field and Description
static String	ATTR_BOUNDING_BOX bounding box of the clustered points as String
static String	ATTR_BOUNDING_BOX_GEOM bounding box of the clustered points as Poligon Geometry
static String	ATTR_COUNT
static String	ATTR_COUNT_UNIQUE
static String	ATTR_GEOM
static String	ATTR_NORM_COUNT
static String	ATTR_NORM_COUNT_UNIQUE

Constructor Summary

Constructors

Constructor and Description
PointStackerProcess()

Method Summary

Modifier and Type	Method and Description
SimpleFeatureCollection	execute(SimpleFeatureCollection data, Integer cellSize, Boolean argWeightClusterPosition, Boolean argNormalize, PointStackerProcess.PreserveLocation preserveLocation, ReferencedEnvelope outputEnv, Integer outputWidth, Integer outputHeight, String cql, ProgressListener monitor)

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

ATTR_GEOM

public static final String ATTR_GEOM

See Also:

Constant Field Values

ATTR_COUNT

public static final String ATTR_COUNT

See Also:

Constant Field Values

ATTR_COUNT_UNIQUE

public static final String ATTR_COUNT_UNIQUE

See Also:

Constant Field Values

ATTR_BOUNDING_BOX_GEOM

public static final String ATTR_BOUNDING_BOX_GEOM

bounding box of the clustered points as Poligon Geometry

See Also:

Constant Field Values

ATTR_BOUNDING_BOX

public static final String ATTR_BOUNDING_BOX

bounding box of the clustered points as String

See Also:

Constant Field Values

ATTR_NORM_COUNT

public static final String ATTR_NORM_COUNT

See Also:

Constant Field Values

ATTR_NORM_COUNT_UNIQUE

public static final String ATTR_NORM_COUNT_UNIQUE

See Also:

Constant Field Values

Constructor Detail

PointStackerProcess

public PointStackerProcess()

Method Detail

execute

public SimpleFeatureCollection execute(SimpleFeatureCollection data,
                                       Integer cellSize,
                                       Boolean argWeightClusterPosition,
                                       Boolean argNormalize,
                                       PointStackerProcess.PreserveLocation preserveLocation,
                                       ReferencedEnvelope outputEnv,
                                       Integer outputWidth,
                                       Integer outputHeight,
                                       String cql,
                                       ProgressListener monitor)
                                throws ProcessException,
                                       TransformException

Throws:

ProcessException

TransformException