PointCloudMerger

Receives new component values from point clouds connected to the Supplier port.

The source of new component values for point clouds that enter through the Requestor port.

Requestor points that find a Supplier.

Requestor points that do not find a Supplier.

Supplier points that are found by at least one Requestor.

Point clouds output via this port will have an additional reference_count component added, specifying the number of times each point was referenced.

Supplier points that are not found by any Requestor.

Supplier points with the same Join On component values as an earlier Supplier point.

If Group By attributes are selected, features with the same values in the Group By attributes are grouped together, and point clouds will only be merged with other point clouds in the same group.

Process At End (Blocking): This is the default behavior. Processing will only occur in this transformer once all input is present.

Process When Group Changes (Advanced): This transformer will process input groups in order. Changes of the value of the Group By parameter on the input stream will trigger processing on the currently accumulating group. This may improve overall speed (particularly with multiple, equally-sized groups), but could cause undesired behavior if input groups are not truly ordered.

Considerations for Using Group By

There are two typical reasons for using Process When Group Changes (Advanced) . The first is incoming data that is intended to be processed in groups (and is already so ordered). In this case, the structure dictates Group By usage - not performance considerations.

The second possible reason is potential performance gains.

Performance gains are most likely when the data is already sorted (or read using a SQL ORDER BY statement) since less work is required of FME. If the data needs ordering, it can be sorted in the workspace (though the added processing overhead may negate any gains).

Sorting becomes more difficult according to the number of data streams. Multiple streams of data could be almost impossible to sort into the correct order, since all features matching a Group By value need to arrive before any features (of any feature type or dataset) belonging to the next group. In this case, using Group By with Process At End (Blocking) may be the equivalent and simpler approach.

Note: Multiple feature types and features from multiple datasets will not generally naturally occur in the correct order.

As with many scenarios, testing different approaches in your workspace with your data is the only definitive way to identify performance gains.

Specifies which components are used to match up Requestor and Supplier points.

Two points are considered to match only if the values for ALL components are equal.

If more than one Supplier point has the same set of values, all points after the first will not be merged with Requestors, and will instead be output the DuplicateSupplier port.

Conflicts occur when Requestors and Suppliers both have a component with the same name.

• Use Requestor: If a conflict occurs, the Requestor values will be maintained.
• Use Supplier: If a conflict occurs, the Supplier values will be transferred onto the Requestor.