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tpg-land
144 post(s)
#12-Jun-18 21:06

Greetings!

Working on summing point values falling within boundaries utilizing the handy Spatial Overlay tool. However...

Looking closer at my data I have physical barriers that in the real world should exclude the counting of some of those point values. Barriers such as a River or Highway.

Using a Query, is it possible to sum all Point values within a boundary only where the centroid of the boundary is located "inside" the boundary and barrier. This description is hard to write and probably harder for you to understand!

I want to sum all except those on the other side of the barrier from the centroid...

Please see the attached example.

Thanks for your help!

Scott

Attachments:
Sum_within_Boundary_except_beyond_barrier.map

tjhb

8,168 post(s)
#12-Jun-18 23:07

You could do this completely in SQL.

Roughly:

  • for each centre, find all points within radius
  • for each matching point, draw a tie line between the point and the centre
  • exclude any point for which the tie line intersects some barrier line [optionally, depending on the movement model: an odd number of times]
  • sum values for the remaining points

An easier option is to split the buffer (radius areas) with the barrier lines in the GUI, then treat each resulting part-buffer as the relevant area for each point.

tpg-land
144 post(s)
#13-Jun-18 16:00

tjhb,

Thanks for the GUI suggestion, didn't think of that!

Scott

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