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LineOnAreaOverlayer

Performs a line-on-area overlay. Each input line is split at any area boundaries it intersects, and attributes are shared between related lines and areas (spatial join).

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Typical Uses

  • Splitting lines where they cross the boundary of a polygon
  • Identifying which polygons contain or intersect lines
  • Identifying lines that intersect or fall within areas

How does it work?

The LineOnAreaOverlayer compares lines and polygons, splitting the lines where they intersect with a polygon boundary. Each resulting piece receives the attributes of the area(s) it is contained in, and each containing area receives the attributes of the line(s) that either fall within or intersect it (a spatial join). Features also receive a count of the number of overlaps encountered.

Aggregates can either be deaggregated before processing or rejected.

Usage Notes

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.

Reference

Processing Behavior

Group-Based

Feature Holding

Yes

Dependencies  
FME Licensing Level FME Professional Edition and above
Aliases  
History  
Categories

Filters and Joins

Spatial Analysis

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Examples may contain information licensed under the Open Government Licence – Vancouver