Re: AI-GEOSTATS: Re: standardized anomaly

2006-08-28 Thread sebastiano trevisani
Hi Isobel I would like to use this transformation to deal with a 3D data set characterized by a peculiarity (well, this is quite common!) in the horizontal spatial variability. In particular if I divide the dataset in horizontal layers I see that horizontal variograms show a similar shape  but w

Re: AI-GEOSTATS: Intrinsic Hypothesis

2006-08-28 Thread Gerald van den Boogaart
On Montag, 28. August 2006 07:42 schrieb [EMAIL PROTECTED]: > Do stationary hypothesis variograms have a sill, Yes, variograms of weakly stationary random fields have a sill: the variance of the field. > and intrisic hypothesis variograms have no sill. They might have no sill, but they also m

AI-GEOSTATS: Re: standardized anomaly

2006-08-28 Thread Isobel Clark
Sebastiano   Your standardisation produces a mean of zero and a standard deviation of 1, without changing the characteristics of the semi-variogram (range, relative nugget effect etc.)   I presume you will standardise each 'layer' separately? Then use a 3D search which does not include samples

RE: AI-GEOSTATS: Re: standardized anomaly

2006-08-28 Thread Bill Northrop
Good morning Sebastiano, I found your problem interesting and I thought I would respond in this fashion. I have done quite a bit of research on similar layered databases on fluvial mineral deposits and found that if one did vertical (at right angles to the contacts of the layers) variograms

AI-GEOSTATS: Re: Intrinsic Hypothesis

2006-08-28 Thread Isobel Clark
Digby   Some simplistic definitions which might help:   (o) "stationary" implies that every location in the study area has a potential statistical distribution with the same mean and standard deviation. That is, all your samples come from the same distribution.   (o) "intrinsic hypothesis" im

AI-GEOSTATS: Re: standardized anomaly

2006-08-28 Thread sebastiano trevisani
Hi Isobel Yes, the standardization is made for each layer separately (and so the back transformation). Actually I'm going to calculate the anomalies...and then let's see! In this case I'm lucky because of the sampling along Z is regular. Sincerely Sebastiano At 12.46 28/08/2006, Isobel Clark wrot

RE: AI-GEOSTATS: Re: standardized anomaly

2006-08-28 Thread sebastiano trevisani
Hi Bill Thank you for your mail. In my case of study there are not sharp boundaries (or at least it seems so!) but there is a gradual and fast decrease in horizontal spatial variability going in depth. Sincerely Sebastiano At 12.48 28/08/2006, you wrote: Good morning Sebastiano, I found your pr

Re: AI-GEOSTATS: Spatio-temporal interpolation of circular variables

2006-08-28 Thread Nelson Luna Silvestre
Thanks for your replies - I am now trying to get access to the mentioned papers, which may well be an even rougher quest. Best Regards, Nelson On 8/25/06, Raimon Tolosana <[EMAIL PROTECTED]> wrote: Hello, list just a short comment: recall that sines and cosines are bound to sum to one once squ

RE: AI-GEOSTATS: Re: standardized anomaly

2006-08-28 Thread Bill Northrop
Hullo Sebastiano,   It sounds as if the Isobel's suggestion of a limited 3D search is the best solution.   The resultant models per layer should tell you if your approach has been correct, especially if you do a trial run with an anisotropic model and search first to see what spatial patte

RE: AI-GEOSTATS: Re: standardized anomaly

2006-08-28 Thread sebastiano trevisani
Hi Bill Yes, my idea is to conduct interpolations along layers (well, performing a "tricky" 3D interpolation only to speed up the process). Well, I'll already know that the shape and the range of the horizontal variograms along Z doesn't change too much. I have some doubt about anisotropy ...but

AI-GEOSTATS: comparing spatial point patterns ?

2006-08-28 Thread Klemens Barfus
Dear list members, searching the archive of the list and the web, I have difficulties to get an access to suitable methods for the following problem: I have simulations of a Monte Carlo radiative transfer model, where the path of photons is tracked inside an atmospheric volume. I stored a horizo