This transformer performs a line-on-line overlay. During the overlay, all input lines are intersected against each other and resultant line features are created and output. Intersection points are turned into point features that contain the merged list of attributes of the original intersected lines.
The Group By parameter specifies a series of attributes that must match on the features before they are considered for overlaying. This can be used to ensure that the overlay occurs only on certain groups of features. Click the browse button to select from a list of attributes.
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 holds the number of line features that intersected the resultant feature.
No: All collinear segments are reduced to one representative segment.
Yes: All collinear segments are output.
Full: All operations are logged.
Limited: Underlying intersection operations are not logged.
Specifies how attributes should be accumulated. If Drop Attributes is selected, all incoming attributes are removed from the features. Merge Attributes merges all attributes from overlapping segments. Get Attributes From One Representative Feature takes all attributes from one representative feature.
When Separate Collinear Segments is Yes, and Accumulation Mode is Merge Attributes, this value prefixes all incoming attributes on collinear segments. It does not affect node output.
Allows you to specify a List Name.
If specified, a list of the attributes of each line that overlapped an output segment is made. This allows later inspection of overlapping segment attributes.
Note: List attributes 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 list attribute transformers are displayed in the Contents pane of the Transformer Help under Lists. Alternatively, AttributeExposer can be used.
When choosing to output only one segment for each collinear group, it may be difficult to predict which of the "original" geometries and attributes are preserved. In general, the features that arrive at the transformer FIRST will be the ones that form the separate segments. Use the FeatureHolder or Sorter transformers to change the sequence of features if this is important.
- This transformer will preserve measures, based on the rules for the order of features described above.
- Aggregates are not supported by this transformer.
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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