Adri�n > > The variogram we most to use is these create with > the residuals (mainly spline residuals)? Yes. Theoretically you should use the residuals calculated by first stage universal kriging. However, there are many published case where authors have found virtually any method of trend removal to be adequate: median polish, spline, polynomial trends and so on.
> > My preoccupation is relate with the magnitude of > the estimation variance, > > it is underestimate if I use residual variogram? Yes. > > In these case is possible reconvert the residual > variogram to wall > > variogram by addition of the effect of drift > previously calculate? Not really. If you use polynomial trend surface analysis, you can build an Analysis of Variance Table to find the 'true' residual variance to inflate the model. I prefer to use a cross validation approach, to see how much inflation is needed and then check that it has been removed. > > The case is that variogram create whit > untransformed data is inconsistent > > by the presence of the inner drift. I am not sure what you mean by "inconsistent". It is certainly mathematically unstable. Isobel Clark http://uk.geocities.com/drisobelclark/Contents.html __________________________________________________ Do You Yahoo!? Everything you'll ever need on one web page from News and Sport to Email and Music Charts http://uk.my.yahoo.com -- * To post a message to the list, send it to [EMAIL PROTECTED] * 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 [EMAIL PROTECTED] 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
