I like this question. The more points you use, presumably the better the estimation will be. In practice however, the influence of distant observations, especially with intervening closer observations, is very slight. Computationally the solution grows much more complex as the number of observations is increased. It's more efficient to solve many many small systems (n=4 closest points) than one global system (n=all points), for example.
I don't think there is any reason to include points more distant than the range of your covariance structure(s), as those observations won't have any weight. Personally, I tend to use between 8 and 16 points, but others with more experience may employ more. I'm probably just more impatient for results! Yours, Ashton On Friday 30 June 2006 10:43 am, Alí Santacruz wrote: > Dear list members, > > I have a very simple question (I think): > > When I want to perform a kriging, I must define the number of nearest > observations that should be used for the kriging prediction, or a maximum > distance from the prediction location. > > What criteria should I use to set these parameters? Which is the optimum > number of nearest neighbors? > > Any comment is welcome. > > Sincerely, > > Alí M. Santacruz > M.Sc. Geomatics, Student > National University of Colombia > Bogotá D.C. > > _________________________________________________________________ > Charla con tus amigos en línea mediante MSN Messenger: > http://messenger.latam.msn.com/ > > + > + To post a message to the list, send it to [email protected] > + To unsubscribe, send email to majordomo@ jrc.it with no subject and > "unsubscribe ai-geostats" in the message body. DO NOT SEND > Subscribe/Unsubscribe requests to the list + As a general service to list > users, please remember to post a summary of any useful responses to your > questions. + Support to the forum can be found at > http://www.ai-geostats.org/ -- Ashton Shortridge Assistant Professor [EMAIL PROTECTED] Dept of Geography http://www.msu.edu/~ashton 235 Geography Building ph (517) 432-3561 Michigan State University fx (517) 432-1671 Geography Has moved! Map: http://www.rsgis.msu.edu/images/parking-map.gif + + To post a message to the list, send it to [email protected] + To unsubscribe, send email to majordomo@ jrc.it with no subject and "unsubscribe ai-geostats" in the message body. DO NOT SEND Subscribe/Unsubscribe requests to the list + As a general service to list users, please remember to post a summary of any useful responses to your questions. + Support to the forum can be found at http://www.ai-geostats.org/
