Matheron used the term spherical to describe the semi-variogram model which represents the concept of two overlapping 'spheres of influence'. The formula is actually the geometric calculation of the amount by which two spheres of diameter 'a' (range of influence) do NOT overlap when their centres are separated by a given distance.
The exponential model contains an exponential term and is exactly equivalent to the 'exponential decay' beloved of economists and other predicters. BTW: the Gaussian is so-called simply because it is the same shape as a Normal cumulative frequency plot (ogive). Isobel Clark http://uk.geocities.com/drisobelclark/resume/Publications.html --- "Serele, Charles" <[EMAIL PROTECTED]> wrote: > Hi all, > > Does anyboby can explain to me the origin of the > variogram models: spherical > and exponential ? Why the names spherical and > exponential ? > > Sincerely > > Charles __________________________________________________ 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
