PointOnAreaOverlayer

TheGroup Byparameter 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: seeAbout Parallel Processingfor detailed information.

This parameter determines whether or not thetransformer should perform the work across parallel processes.If it is enabled,a process will be launched for each group specified by theGroupByparameter.

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 theGroup Byparameter 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.

TheOverlap Count Attributeadded to output area features holds the number of point features that they contained.

IfAreas Firstis set toYes,then the PointOnAreaOverlayer assumes that allAreafeatures will enter the transformer before anyPointfeatures.This can reduce memory use of the PointOnAreaOverlayer if you have manyPointfeatures to overlay.Any furtherAreafeatures that arrive after the firstPointfeature will be logged with a warning and discarded.

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 theConflict Resolutionparameter.

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 thePrefixparameter.

Only Use Incoming: The original feature will have all of its attributes removed,except geometry attributes that start withfme_.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 theAccumulation Modeparameter is set toPrefix Incoming,this value will prefix attributes that are being added to the original feature from the incoming feature.

If the optionalList Nameis supplied,the attributes of each area containing an output point are added to that point's list,and the attributes of each point contained by an output area are added to that area's list.

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 asListExploderorListConcatenator.All attribute list transformers are displayed in the Contents pane of the Transformer Help underLists.Alternatively,AttributeExposercan be used.