Performs an overlay of points on points.
The Group By parameter specifies a series of attributes that must match on the point and polygon features before the attributes will be merged. This can be used to ensure that the overlay occurs only on certain groups of features.
Note: How parallel processing works with FME: see About Parallel Processing for detailed information.
This parameter determines whether or not the transformer should perform the work across parallel processes. If it is enabled, a process will be launched for each group specified by the Group By parameter.
Parallel Processing Levels
For example, on a quad-core machine, minimal parallelism will result in two simultaneous FME processes. Extreme parallelism on an 8-core machine would result in 16 simultaneous processes.
You can experiment with this feature and view the information in the Windows Task Manager and the Workbench Log window.
Yes: This transformer will process input groups in order. Changes on the value of the Group By parameter on the input stream will trigger batch processing on the currently accumulating group. This will improve overall speed if groups are large/complex, but could cause undesired behavior if input groups are not truly ordered.
No: This is the default behavior. Processing will only occur in this transformer once all input is present.
The Overlap Count Attribute added to output point features holds the number of point features to which the point was near.
Each input point has the attributes from any other point within the Point Tolerance distance merged onto it.
If attributes on the incoming and original feature share the same name, but are not geometry attributes that start with fme_, then they are deemed conflicted.
Merge Incoming: The original feature will retain all of its own un-conflicted attributes, and will additionally acquire any un-conflicted attributes that the incoming feature has. This mode will handle conflicted attributes based on the Conflict Resolution parameter.
Prefix Incoming: The original feature will retain all of its own attributes. In addition, the original will acquire attributes reflecting the incoming feature’s attributes, with the name prefixed with the Prefix parameter.
Only Use Incoming: The original feature will have all of its attributes removed, except geometry attributes that start with fme_. Then, all of the attributes from one (arbitrary) incoming feature will be placed onto the original.
Use Original: If a conflict occurs, the original values will be maintained.
Use Incoming: If a conflict occurs, the values of the incoming will be transferred onto the original.
If the Accumulation Mode parameter is set to Prefix Incoming, this value will prefix attributes that are being added to the original feature from the incoming feature.
If the optional List Name is supplied, each output point will also have an attribute list containing the attributes from each point that is within the Point Tolerance distance.
Note: Attribute lists are not accessible from the output schema in Workbench unless they are first processed using a transformer that operates on them, such as ListExploder or ListConcatenator. All attribute list transformers are displayed in the Contents pane of the Transformer Help under Lists. Alternatively, AttributeExposer can be used.
- When attributes are merged between features, existing attributes are not replaced. Therefore, if the points and areas being overlaid have attributes with the same name, then the values will not be transferred from one to the other. You can avoid this problem by renaming (AttributeRenamer), prefixing (AttributeExpressionRenamer), or removing (AttributeRemover) attributes to avoid name collisions.
- Aggregates are not supported by this transformer.
- Note that where Point geometries are expected as input, PointCloud geometries are not supported.
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.
FME Licensing Level
FME Professional edition and above
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