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How to construct lines from one dataset of points and one dataset of pairs

  • March 3, 2019
  • 4 replies
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nicholas
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I have two tables.

One is a dataset of points, each point has a unique ID

The other is a (attribute only) dataset of pairs, each record refers to two points, via their unique ID

How do I construct a feature dataset of lines? Each line consisting of two points.

 

To re-phrase, how do I add line geometry to the dataset of pairs, using the appropriate points from the point dataset, based on the unique ID of the from and to points?

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    4 replies

    danilo_fme
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    • danilo_fmeCelebrity
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    • 2077 replies
    • March 3, 2019

    Hi @nicholas

    I suggest you to use the transformer FeatureMerger - to find the relation between the two datasets by ID.

     

    After the use the transformer LineBuilder.

    Thanks,

    Danilo

     

    Partner Solutial Brazil - www.solutial.com.br
    takashi
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    • takashiCelebrity
    • 7843 replies
    • March 4, 2019

    A possibly way I can think of is:

    1. Merge the first point geometry to the features containing pair of IDs, with a FeatureMerger (Join On: ID of the first point, Feature Merge Type: Geometry).
    2. Extract coordinates (x, y) from the original point geometries with the CoordinateExtractor (Mode: Specify Coordinate, Coordinate Index: 0), and merge the (x, y) to the features output from the Merged port of the first FeatureMerger, with another FeatureMerger (Join On: ID of the second point, Feature Merge Type: Attributes Only).
    3. Use the VertexCreator (Mode: Add Point) to add the second point to the features output from the Merged port of the second FeatureMerger.
    Why not inspect features with Visual/Data Preview and Feature/Record Information before writing them into a destination dataset?
    nicholas
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    • nicholasContributor
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    • 116 replies
    • March 4, 2019

    A possibly way I can think of is:

    1. Merge the first point geometry to the features containing pair of IDs, with a FeatureMerger (Join On: ID of the first point, Feature Merge Type: Geometry).
    2. Extract coordinates (x, y) from the original point geometries with the CoordinateExtractor (Mode: Specify Coordinate, Coordinate Index: 0), and merge the (x, y) to the features output from the Merged port of the first FeatureMerger, with another FeatureMerger (Join On: ID of the second point, Feature Merge Type: Attributes Only).
    3. Use the VertexCreator (Mode: Add Point) to add the second point to the features output from the Merged port of the second FeatureMerger.

    I have done exactly that.

    It works, but it seems not elegant.

    I was hoping that there was a way to merge the geometries directly without converting the points from geometry to coordinate values and back to geometry again.

    M
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    • markatsafe
    • 1891 replies
    • March 8, 2019

    @nicholas I think I would go with @takashi 's approach - it would be much clearer for others to understand the workflow - even if it does require extracting the coordinates. However, there is an obscure part of the FeatureMerger functionality that can build geometries: Geometry Merge Type: Build Lines From Points. I've never used this before so thought this might be an excuse to try that. Here is the result:

     

    Here's the workspace (2018.1): createlinesfromnodes.fmwt

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