PointOnAreaOverlayer

Performs a Point in Polygon overlay. Points receive containing area attributes, and areas receive contained point attributes (spatial join).

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Typical Uses

  • Finding which areas that points fall inside
  • Finding which and how many points are contained within areas

How does it work?

The PointOnAreaOverlayer compares points and polygons. Each point receives the attributes of the area(s) it is contained in, and each containing area receives the attributes of each point it contains.

Intersections between area features are not computed. FME consider points on the boundary of an area as “in”, and so if a point falls exactly on the line between two polygons, it will be considered "in" both areas.

Aggregates can either be deaggregated before processing or rejected.

Examples

Usage Notes

  • If you have a lot of features to process, you can improve overlay performance by also using the Clipper transformer. The Clipper also provides different options for a point that falls exactly on a line. See the Clipper example from the FME Community for information on how to use less memory using the Clippers First parameter.
  • If you have a lot of Point features in particular, you can reduce memory usage of the PointOnAreaOverlayer by using the Areas First parameter.
  • Note that where Point geometries are expected as input, PointCloud geometries are not supported.
  • The PointOnAreaOverlayer does not have a tolerance option for position.

Choosing a Spatial Transformer

Many transformers can assess spatial relationships and perform spatial joins - analyzing topology, merging attributes, and sometimes modifying geometry. Generally, choosing the one that is most specific to the task you need to accomplish will provide the optimal performance results. If there is more than one way to do it (which is frequently the case), time spent on performance testing alternate methods may be worthwhile.

To correctly analyze spatial relationships, all features should be in the same coordinate system. The Reprojector may be useful for reprojecting features within the workspace.

Configuration

Input Ports

Output Ports

Parameters

Editing Transformer Parameters

Using a set of menu options, transformer parameters can be assigned by referencing other elements in the workspace. More advanced functions, such as an advanced editor and an arithmetic editor, are also available in some transformers. To access a menu of these options, click beside the applicable parameter. For more information, see Transformer Parameter Menu Options.

Defining Values

There are several ways to define a value for use in a Transformer. The simplest is to simply type in a value or string, which can include functions of various types such as attribute references, math and string functions, and workspace parameters. There are a number of tools and shortcuts that can assist in constructing values, generally available from the drop-down context menu adjacent to the value field.

Dialog Options - Tables

Transformers with table-style parameters have additional tools for populating and manipulating values.

Reference

Processing Behavior

Group-Based

Feature Holding

Yes

Dependencies  
FME Licensing Level FME Professional Edition and above
Aliases  
History  

FME Community

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Examples may contain information licensed under the Open Government Licence – Vancouver and/or the Open Government Licence – Canada.