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How do I use a conditional statement with the clipper tool?

  • December 18, 2017
  • 1 reply
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Hi I'm a new user to FME, but I am familiar with model building.

I have a process that takes LiDAR point clouds and turns them into DEMs. A branch of this process takes the outline of the initial point cloud and clips the DEM to the point cloud boundary. There are two possible point cloud outlines created by this process (depending on if there are holes in the data).

How do I get the clipper to use outline A if it exists, else use outline B?

I know the logic required here, I just can figure which transformers / settings / parameters to use to get this process to run

Best answer by jdh

Depending on the actual workflow one or more of the following should work:

Use a variableSetter upstream to specify which outline to use, just before the clipper use a variableRetriever and a tester to get just the outline you want

create a priority attribute on the outlines (A: 1, B:2) and a sorter and sampler (1st feature) just before the clipper.

create an attribute on the DEM (hole/no_hole) and the corresponding attribute on the outlines, and use a Group-By on the clipper

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1 reply

jdh
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  • Best Answer
  • December 18, 2017

Depending on the actual workflow one or more of the following should work:

Use a variableSetter upstream to specify which outline to use, just before the clipper use a variableRetriever and a tester to get just the outline you want

create a priority attribute on the outlines (A: 1, B:2) and a sorter and sampler (1st feature) just before the clipper.

create an attribute on the DEM (hole/no_hole) and the corresponding attribute on the outlines, and use a Group-By on the clipper