[Scilab-users] spatial correlation coefficient: Is the MATLAB corrcoef function doing the job?

Heinz heinznabielek at me.com
Fri Feb 9 19:43:35 CET 2018


1	The nearest neighbour distribution of N points in a 3d-Volume with
radius R is given by
W(r) = 1 - exp[ - N (r/r)^3] and this is a Weibull distribution and not a
Poisson distribution. The WIKI article, while correct, is a typical case
where high level statisticians are trying to make simple things look very
complicated.

2	Comparing the experimental distribution with the above prediction is
made complicated as the manufactured object has small hard spheres that push
each other apart in the manufacturing process and the Weibull is modified
anyway.

3	I am sill searching for a 3d spatial characterization coefficient
that differentiates between purely random arrangements and gradual regular
arrangements.

Heinz

-----Original Message-----
From: users [mailto:users-bounces at lists.scilab.org] On Behalf Of Rafael
Guerra
Sent: 09 February 2018 10:17
To: Users mailing list for Scilab <users at lists.scilab.org>
Subject: Re: [Scilab-users] spatial correlation coefficient: Is the MATLAB
corrcoef function doing the job?


Q: "I have 10,000 xyz data and want to know, if there is some regularity in
them or if they are more or less random"
A:  look for tests of spatial randomness
(https://en.wikipedia.org/wiki/Complete_spatial_randomness ) . If The
experimental nearest neighbor distribution obtained previously can be
compared to the expected Poisson distribution.





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