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Hi FME community,

 

I'm creating a workspace to automate a proportional spatial sum.

I have polygons with employment data.

And I have bus stops that I'm using to create multiple buffers as my zones of interest.

 

I'm testing this with zones I've already caculated with MapInfo GIS software so I know what values I'm suppose to have in the end, and i'm able to compare this with FME workspace results.

 

I get the expected result when I aggregate all my stops points from all buses indifferently:

proportional spatial sum_all_stops 

But I also need those stats for each bus separately. To do so, instead of aggregating indifferently all points, I do it with a group by using my bus name attribute.

But the results are way off.

proportional spatial sum_by_bus 

 

If I add a tester before the buffer, in order to filter only one bus, I have the exact result. As soon as there is more than one zone of interest the results are false.

My guess is that I don't know how to use the clipper correcly with multiple zones as clippers (even if the clipper type is on "multiple clippers").

Any ideas or other method to accomplish this ?

 

Thank you for taking the time to read this

I'm not 100% sure that I fully understand the process​ or the problem but could this be related?

The total input area of the clippees usually matches the ​total output of the clipped area. Meaning that none of the output clipped areas should overlap.

If some of the clippers​ overlap you might get unexpected results.

At least this has been my experience. Perhaps the AreaOnAreaOverlayer might give you better results?​

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