Hello, AI_Geostats members In some model for variograms the Range (the distance at which dependency is disappear) is differ from the Range parameter in the model. For example in the exponential semivariogram model (bellow) range = 3 * (range parameter) (reference: the user manual of GS+ software) My question is that what is the relationship between range and range parameter in Rational Quadratic Semivariogram Model? Cressie,1993 (page 61) has written the model as: g(h) = c0 + cr*(h^2)/(1 + h^2/ar) where cr and ar are the sill parameter and range parameter. Thank you for your attention. Yadollah Waghei Dep.of Biostatistics Tarbiat Modarres Univ.(Tehran)Po.Box: 14115-111 Tel:8011001-3872 Fax:8007989 ___________________________________________________________________________ Visit http://www.visto.com/info, your free web-based communications center. Visto.com. Life on the Dot. -- * 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