LeftRightSpatialCalculator

Before being sent out through the Output port, each Candidate feature will have a list of its relative positions to each of the Base features attached to it. Each element of the list has two pieces of information:

• a "base_id" which identifies the base
• the computed relative "position"

Base features are dropped after being used.

Any Base feature that is not a line is output through this port. All null and aggregate Candidate features are output through this port. The valid part will output through the Output port, and the invalid part will output through the <Rejected> port.

If you choose Group By attributes, Candidates are only compared against Bases that have the same values in these 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

Parameter	Number of Processes
No Parallelism	1
Minimal	coresThe processor, or CPU, is the physical part of the computer that performs mathematical calculations. It is the most important part of a computer system. Traditional processors have only one core on the processor, meaning that at any given time, only one set of calculations is being performed. If a processor is dual-core, this means the single chip contains hardware for two processors, now called cores to distinguish them from the single chip, running simultaneously, side by side. (Source: http://www.ehow.com/facts_5730257_computer-core-processors_.html) / 2
Moderate	exact number of cores
Aggressive	cores x 1.5
Extreme	cores x 2

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.

No: This is the default behavior. Processing will only occur in this transformer once all input is present.

By Group: 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.

If you choose Yes (default), the algorithm will use only the center of mass of passed in Candidates instead of the whole geometry.

If you choose Yes, the algorithm will compute only at the point on the Base line that is closest to the first or "center of mass" point.

Define whether only a Single Base will be supplied, or whether Multiple Bases will be supplied. If you choose Bases First, all Base features will enter the transformer first, before any Candidate features.

Choose the Base attribute whose value will be used to identify it in the list of relative positions attached to each output Candidate.

Specify the name of the list attribute that will be added onto all output Candidate features, and that will contain the relative positions.