Natural Resource Biometrics1^{st} order Spatial StatisticsFormated version of this page for printingHopkins' Index of aggregationHopkins' index of agregation is the ratio of the distance from a tree to it's nearest neighbor and the distance from random points within the same space to their nearest neighbor tree. where d_{(pti)i} is the distance from a random point to it's nearest neighbor tree. d_{(tti)i} is the distance from a tree to it's nearest neighbor tree. This test has a F distribution with F(2m,2m) (Hopkins, 1954). Figure 1. A example of how the Hopkin data is collected. The red dots are trees. The gold dots are random points. We collect the 1^{st} nearest neighbor trees to the point distances and the tree to tree nearest neighbors. Byth and Ripley (1980) presented standardized index based on this test as: This index has a Normal null distribution N(1/2,1/12m).
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Natural Resources Biometrics by David R. Larsen is licensed under a Creative Commons AttributionShareAlike 4.0 International License . Author: Dr. David R. Larsen Created: October 12, 2011 Last Updated: October 9, 2014 