Hello Everyone,

I am working on recreating the Average Nearest Neighbor tool and was wondering if anybody knows A) does the NN tool in ArcToolbox take into account edge/boundary effects and B) how does the script do this (what method does it use)? Any help in this would be great. So far to account for edge effects in my own work I have created an inner buffer zone for my points and removed all nearest neighbor distances greater than e^(natural log(mean + (2 * standard deviations))). Also, if anybody has any pointers on what other edge-effect corrections I could use.

Thank you all,

Winn

I am working on recreating the Average Nearest Neighbor tool and was wondering if anybody knows A) does the NN tool in ArcToolbox take into account edge/boundary effects and B) how does the script do this (what method does it use)? Any help in this would be great. So far to account for edge effects in my own work I have created an inner buffer zone for my points and removed all nearest neighbor distances greater than e^(natural log(mean + (2 * standard deviations))). Also, if anybody has any pointers on what other edge-effect corrections I could use.

Thank you all,

Winn

I would pose the question: if you are going to the trouble of "re-creating" the NNI statistic (I assume in Python) then why are you not implementing a more modern counterpart (i.e., K, G-hat, F-hat) that accounts for the know limitations of the Clarke-Evans NNI? ESRI has developed methods for linking R and ArcGIS (through Python) that could be leveraged to provide a suite of well developed PPA statistics.

I would recommend the following readings in point pattern statistics and the NNI:

Baddeley, A.J. and Gill, R.D. (1997) Kaplan-Meier estimators of interpoint distance distributions for spatial point processes. Annals of Statistics 25:263-292.

Cressie, N.A.C. (1991) Statistics for spatial data. John Wiley and Sons, 1991.

Diggle, P.J. (1983) Statistical analysis of spatial point patterns. Academic Press.

Donnelly, K. (1978) Simulations to determine the variance and edge-effect of total nearest neighbour distance. In Simulation methods in archaeology, Cambridge University Press, pp 91�??95.

Hanisch, K.-H. (1984) Some remarks on estimators of the distribution function of nearest-neighbour distance in stationary spatial point patterns. Statistics 15:409�??412.

Ripley, B.D. (1988) Statistical inference for spatial processes. Cambridge University Press.