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How to filter point cloud based on dynamic attribute values?

  • 6 November 2017
  • 4 replies
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I tried looking for similar queries but I need some help with this asap. To explain my question further, I have a point cloud with x, y, z and the fourth column is a componentID (after having done connected components) I have a text file which consists of a string of component ID values.

I am trying to filter the point cloud based on the number of component ID values in my text file. So, I have a couple of questions.

1. I am trying the basic method by filtering the point cloud based on the value of the component but I keep getting the following error

PointCloudFilter(PointCloudEvaluationFactory): Attribute 'C1' is specified in an expression but is not present on the feature. Please ensure the feature has all referenced attributes

I am not really sure how to solve this. Because if I use an attribute creator to assign values to C1 independent of the values from text file, it works fine. But when I integrate it with text file it goes into error.

2. My text file will not always contain 3 values. It will vary. How do I make my workflow such that my point cloud is filtered dynamically according to the number of values in my text file.

I guess this is too specific hence I have attached a template file. I have been struggling with this the last 2 days and really appreciate some help!

Thank you

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Best answer by daveatsafe 7 November 2017, 01:44

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daveatsafe
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Hi @sraapril,

In order to put the text file attributes onto the point cloud, you must explicitly merge the features using a FeatureMerge transformer. I am attaching a modified workspace illustrating how to use this transformer with an indiscriminate merge.

pointmatch2.fmw

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Hi @DaveAtSafe

Thank you very much! This works exactly like I want it to for my question 1.

Is there a workaround for question 2? I need to filter my point cloud based on all the values from the incoming list. However it is dynamic. Is there a way to code for the expression in point cloud filter?

Sravanthi

daveatsafe
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Userlevel 2
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Hi @sraapril,

For question 2, we can do this if we modify the text file into a proper CSV file, with columns for the point_source_id and matching classification.

I created a new CSV file in a text editor, in the form:

point_source_id,classification23450,622685,723949,8

I then changed the workspace to use a PointCloudSplitter and ListSearcher to apply the classification from the CSV.

Please try the attached workspace.

pointmatch3.fmw

las-py.csv

S
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Hi @sraapril,

For question 2, we can do this if we modify the text file into a proper CSV file, with columns for the point_source_id and matching classification.

I created a new CSV file in a text editor, in the form:

point_source_id,classification23450,622685,723949,8

I then changed the workspace to use a PointCloudSplitter and ListSearcher to apply the classification from the CSV.

Please try the attached workspace.

pointmatch3.fmw

las-py.csv

@DaveAtSafe 

 

 

You are incredible! I was working on making my having a text file in the format you just have used. Now you built the workflow further. WOW! 

 

 

Thank you very much! :D

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