Jul The nugget effect is the (semi) variance between two samples which might be taken at almost exactly the same spot. Or, expressed otherwise, the variance of replicated samples.
The total sill is the variance of values within your data set (or, more strictly, within all possible samples). Thus the nugget to not-nugget ratio is the proportion of the variation you can expect to predict with a spatial model, whilst the nugget part is that variation you cannot predict no matter how closely you sample. Isobel http://geoecosse.bizland.com/books.htm ________________________________________________________________________ Want to chat instantly with your online friends? Get the FREE Yahoo! Messenger http://mail.messenger.yahoo.co.uk -- * 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