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Aggregator: Attributes to Average, Weighted by Length?

  • November 12, 2013
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A
Hello,

 

 

I noticed in the Aggregator transformer that there is an option "Attributes to Average, Weighted by Area", is there a way to weight the average by length for a line feature? If not, do you have any recommendations on a different way to get that result?

 

 

Thanks for your help!

 

 

Amanda

Best answer by takashi

Hi Amanda,

 

 

I don't think there is an option to calculate Length weighted average. I would do the following steps.   Before Aggregator: Calculate length of every line feature (LengthCalculator). Calculate (length * attribute value) and set the result to new attribute (ExpressionEvaludator or AttributeCreator). "new attribute value" = "attribute value" * "length"   Aggregator: Calculate sum of the new attribute values and lengths seperately ("Attribute to Sum" parameter).   After Aggregator: Calculate the length weighted average(ExpressionEvaludator or AttributeCreator). "Length Weighted Average" = "sum of new attribute values" / "sum of lengths".   I hope the result will be correct. Wikipedia > Weighted arithmetic mean

 

 

Takashi
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1 reply

takashi
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  • takashiCelebrity
  • Best Answer
  • November 13, 2013
Hi Amanda,

 

 

I don't think there is an option to calculate Length weighted average. I would do the following steps.   Before Aggregator: Calculate length of every line feature (LengthCalculator). Calculate (length * attribute value) and set the result to new attribute (ExpressionEvaludator or AttributeCreator). "new attribute value" = "attribute value" * "length"   Aggregator: Calculate sum of the new attribute values and lengths seperately ("Attribute to Sum" parameter).   After Aggregator: Calculate the length weighted average(ExpressionEvaludator or AttributeCreator). "Length Weighted Average" = "sum of new attribute values" / "sum of lengths".   I hope the result will be correct. Wikipedia > Weighted arithmetic mean

 

 

Takashi
Why not inspect features with Visual/Data Preview and Feature/Record Information before writing them into a destination dataset?

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