Rubens Your approach has been long used in hydrology and similar fields with much success.
The problem with the standard deviation is that it does not include the the 'error' on the estimation of the true drift. To get a composite error you would either have to (a) add your kriging variance to some sort of classical regression variance to get a composite one; (b) use a Universal Kriging (or generalised covariance) approach to estimate the surface with the drift included. In our experience, your estimated surface will not change but your kriging variances will increase slightly. Isobel Clark __________________________________________________ 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
