for each grid density (mean absolute difference). Different grid

densities, different radii, ergo different madogram shapes. Each madogram

may or may not show a range. The trick is to come up with a grid

density that would result in a radius that is more or less equivalent

to the range, to extract maximum interpolation data. Because the

grid is on equal spacing, the problem is finding a range to compare to,

and the only one available would be the global range of the data.

Regards,

Syed

>Overlay a grid on a 2D distribution of random variables Z(x,y) and

useful responses to your questions.

>assign all such variables to the nearest grid node. Then consider

>the distribution of F(i,j) = (ZMAX-ZMIN)(i,j) for any grid node with

>nearby data. For simplicity, assume that the original random variables

>are (locally) normally distributed and that all collected at any node

>have the same mean and standard deviation. What is the distribution

>of F?

>

>My reason for asking is that I am trying to automatically select

>a grid row and column spacing to use in grid-based surface modeling

>and one intuitive criteria is to get a "dense enough" grid that the

>largest ZMAX-ZMIN for any single grid node is small relative to the

>range of Z values in the input data set. (Well, intuitive to me.)

>Then I started wondering what I might conclude if the sampled mean

>plus a couple of standard deviations for the population of such node

>variables was small. And then I got confused.

>

>I am guessing that the distribution of F is standard problem in

>statistics when the data are normal: Given M samples from N(0,1),

>what is the distribution of Zmax-Zmin? But I don't have the right

>"standard" statistics book.

>

>Hmmm. Maybe I am gathering information about the nugget for a data

>set?

>

>Thanks,

>

>Steven Zoraster

>

>--

>* To post a message to the list, send it to ai-geostats@...

>* As a general service to the users, please remember to post a summary of any

>* To unsubscribe, send an email to majordomo@... with no subject and

"unsubscribe ai-geostats" followed by "end" on the next line in the message

body. DO NOT SEND Subscribe/Unsubscribe requests to the list>* Support to the list is provided at http://www.ai-geostats.org

--

* To post a message to the list, send it to ai-geostats@...

* As a general service to the users, please remember to post a summary of any useful responses to your questions.

* To unsubscribe, send an email to majordomo@... with no subject and "unsubscribe ai-geostats" followed by "end" on the next line in the message body. DO NOT SEND Subscribe/Unsubscribe requests to the list

* Support to the list is provided at http://www.ai-geostats.org