Good day Oliver, I have another comment on declustering in addition to the previous comment on negative weights. The weights do not actually change the data values. They change the weight of the data values within the distribution; therefore, weights change the distribution, but not the sample data. One way to think of declustering weights is that they would change the height on the bars of a histogram (more precisely, the contribution of each of the data to the bar height), but not the position of the bars.
The GSLIB book (Deutsch and Journel) has a lot of practical guides to declustering. I have recently written a paper on the specifics of declustering, if you are interested. All the best, Michael _____________________________________________ Michael Pyrcz Ph.D. Candidate Department of Civil & Environmental Engineering University of Alberta (780) 492-3153 [EMAIL PROTECTED] www.ualberta.ca/~mpyrcz -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: July 5, 2003 2:13 AM To: [EMAIL PROTECTED] Subject: AI-GEOSTATS: Declustering hello list, to get the global mean of my data set (484 observation wells) and as a prerequisite for Normal Score Transformation with GSLIB, i declustered my data with polygonal declustering. When standardizing the weights to 1, so that the weights sum up to the number of data, I receive some negative weights. this results in negative values for the observations (nitrate concentration). how do i have to interpret this ? does this require a special treatment? skip them? as I mentioned before, i want to normal score transform the data set prior to simple kriging. many many thanx for some help in advance. Regards, Oliver -- * 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 -- * 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
