AI-GEOSTATS: standardized anomaly

2006-08-25 Thread Sebastiano Trevisani
Dear list member A procedural question for you... I'm thinking to transform my data in a standardized anomaly [i.e. (raw datum- sample average)/sample standard deviation)] and then I`ll perfom the geostatistical analysis on these transformed data. At first glance, I don't see problem in t

AI-GEOSTATS: Re: standardized anomaly

2006-08-25 Thread Isobel Clark
Sebastiano   You will be fine so long as you actually have a "stationary" phenomenon. That is, there is a constant mean and standard deviation over your study area -- no trends, no discontinuities, no changes of behaviour. Such a transformation also assumes that your data follow a fairly symmetri

AI-GEOSTATS: Variogram sill

2006-08-25 Thread [EMAIL PROTECTED]
Hello, I was wondering about some variogram models not having a sill. Does this mean that semi-variogram values can be greater than the population variance, in which case you would have negative covariances, or is the population variance the maximum these models, e.g. linear model, may reach. +

AI-GEOSTATS: Variogram sill

2006-08-25 Thread [EMAIL PROTECTED]
Hello, I was wondering about some variogram models not having a sill. Does this mean that semi-variogram values can be greater than the population variance, in which case you would have negative covariances, or is the population variance the maximum these models, e.g. linear model, may reach. +