Soeren What you have here is sometimes known as a co-located cross semi-variogram and only pairs of samples with both variables can be included in its calculation.
There is a non-co-located semi-variogram (see Cressie's book for example) which looks like gamma(h)=1/2N(h)*sum((z_i-y_j^2) This works best if the variables are standardised (same mean, same standard deviation) and uses all of the samples with either variable. Isobel Clark http://geoecosse.bizland.com/news.html --- Soeren Nymand Lophaven <[EMAIL PROTECTED]> wrote: > Dear list > > I have a question regarding estimation of the cross > semivariogram, > given by: > > gamma(h)=1/2N(h)*sum((z_i-z_j)(y_i-y_j)) > > where y and z are the two variables. My question > simply is: Do y and z > have to be measured at the same locations in order > to estimate the cross > semivariogram ?? > > Best regards / Venlig hilsen > > Søren Lophaven > ****************************************************************************** > Master of Science in Engineering | Ph.D. > student > Informatics and Mathematical Modelling | Building > 321, Room 011 > Technical University of Denmark | 2800 kgs. > Lyngby, Denmark > E-mail: [EMAIL PROTECTED] | > http://www.imm.dtu.dk/~snl > Telephone: +45 45253419 | > ****************************************************************************** > > > -- > * 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 __________________________________________________ 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
