Jack There is a schism in the geostatistical community between those who do and those who don't make gamma(0) equal to 0.
Some people argue that the nugget effect is 'sampling error' and that gamma(0) should equal c0 so that kriging does not honour the data values. It also makes your kriging variances smaller (emphasis). I (personally) find it a bit weird to have smaller supposed errors if you do not trust your data. Software packages differ as to whether they do or do not go to zero. Simplest way to check is to replace your nugget effect by a spherical component with a very short range of influence and see if your answers change. Isobel Clark http://geoecosse.bizland.com/pg2000.htm __________________________________________________ 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
