Question

How does Dissolver compute average?

  • 5 February 2014
  • 4 replies
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I am using dissolver to combine features, grouped by an attribute (SPC_CD). I need to average another attribute (PCNT_CVR).  I am confused by the results I am seeing because they don't apear to be either the mean or median.  I am also not clear about whether Dissolver computes the average for each individual set of overlapping (in this case I am using overlaps) features being dissolved, or does it compute the average for ALL features in a group (i.e. one average for each SPC_CD value)?

 

 

Thanks!

 

katie

4 replies

Userlevel 2
Badge +17
Hi Katie,

 

 

The Dissolver calculates average for each dissolved feature.

 

If all features in a group were dissolved into one feature, average value would be calculated for all features in the group. But if there were disjoint features in the group, average value would be calculated for each dissolved feature, even though they belong to same group.

 

And, you will have to specify the attribute which you need to calculate average to "Attributes to Average" parameter of the Dissolver.

 

 

Takashi
Excellent, thanks Takashi. Do you know if the average is a mean or median? I am assuming it's the mean.

 

 

Kind regards,

 

katie
Userlevel 2
Badge +17
As far as I know, "average" is same as "(arithmetic) mean" in general.

 

http://en.wikipedia.org/wiki/Average

 

Thanks Takashi!

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