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Sorry If you've read this before - I've tried to change the content so that it reflects what I need a little better. This question was marked as a duplicate although I read the the answer to the other question and it didn't answer my query, so was advised to re-post.

I've created thiessen polygons for point data I have in ArcGIS 10.1. Unfortunately the data locations are post-code centroids, and about half of the records are lost due to the fact that they fall in the same post-code centroid as other points.

What I'd like to do is offset same-location points, within the bounds of areas defined by polygons that are in a different layer. I don't want to generate points, as the sampling points already exist.

I would prefer the points to be set apart by area or by polygon length/width - I'd basically like them to be reasonably regularly spaced in relation to the polygons. This is so I can then create thiessen polygons from all of my data points, as it won't consider overlapping points. I would prefer that non-overlapping points be left where they are. I want each of the stacked points to be evenly dispersed within the bounds of each postcode, but the dispersed points to remain in a separate layer from the post code boundaries.

Otherwise if there are any other interpolation methods which would allow me to offset data points or cope with two points in the same location it would be great to know what they are. I expect this could be problematic as each of the points can have different data, which would then become quite difficult to display / visualize as they'd overlap.

I'm having huge difficulties with this and would really, really appreciate your help.

EDIT: I've found a new tool called Disperse Markers - this sounded promising until I discovered you can't limit dispersal by polygon bounds from another layer.

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    You basically want the stacked points to be evenly dispersed in each post-code boundary? – klewis Aug 29 '13 at 18:55
  • Yes - I've explained above (in italics). – Joules Aug 30 '13 at 7:06
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Without knowing what language you are using, its tough to target the answer, but it sounds like you might find some useful hints in checking out the code used for Pack Layouts (JavaScript/D3) which does something like this: https://github.com/mbostock/d3/wiki/Pack-Layout.

This is fundamentally a forced layout diagram, examples of which should be available for most languages. I am guessing your problem could be solved by having repellent forces between points that fall inside of the same boundary, but have them all confined within the overall postcode boundary.

  • I was hoping for some sort of tool within ArcGIS - my programming skills are non-existent. It does look like it's what I need - I will look up forced layouts and get back to you. – Joules Aug 30 '13 at 7:25
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    You might get some more advice by adding ArcGIS to your question tags then. – Dan Aug 30 '13 at 7:36

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