pbrockhill

Hot Spot Results seem dubious

Discussion created by pbrockhill on May 22, 2011
Latest reply on May 24, 2011 by pgibbons
Hi,
I have been experimenting with Hot Spot analysis a bit since my last post and managed to get it working for some point data we required (at least i think i did).
I've now been tasked (after they liked it so much) to extend on it and I'm now working with volume data based on area boundaries.  They would like hot spots done for these.
I went through the same sort of procedure as for points (except not need to integrate and collect events) and I have experimented with analysis based on state or national scales, various distances (based on doing the autocorrelation, and classification types.
Attached are the results of my analysis using Zone of Indifference at a state based distance of 45,000m.  My polygons are very uneven and unevenly dispersed.  some also have no known volume.

When you look at the results (and it gets more confusing when looking at all the different results from different options) you can see where the highest volumes are on the bottom image.  how come after hotspot analysis not all these high volumes are included in a hot spot?  I would have though all these high volumes together would make one hotspot, but do the polygons have to be touching for that to occur?

Other results were putting hotspots where there was low volume counts.  even more confusing.

Am i missing something here?

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