Hello, In general, the primary data will screen the influence of the co-located secondary data, leading to the similarity of the results provided by isotopic cokriging and kriging ignoring this secondary information; see my paper in Math Geol. Goovaerts, P. 1998. Ordinary cokriging revisited. Mathematical Geology, 30(1): 21-42. However, in some situations it is the secondary data that will screen the influence of primary data. It is likely to happen when both variables are strongly correlated and the secondary variable varies more continuously in space than the primary variable, i.e. the secondary variogram has a smaller nugget effect.. See the example in my book pages 219-220. Cheers, Pierre Pierre Goovaerts Chief Scientist at BioMedware Inc. Courtesy Associate Professor, University of Florida President of PGeostat LLC Office address: 516 North State Street Ann Arbor, MI 48104 Voice: (734) 913-1098 (ext. 8) Fax: (734) 913-2201 http://home.comcast.net/~goovaerts/
________________________________ From: [EMAIL PROTECTED] on behalf of Maarten De Boever Sent: Wed 6/7/2006 4:30 AM To: ai-geostats@jrc.it Subject: AI-GEOSTATS: special case of ordinary cokriging Dear all, The potential improvement of cokriging depends on the extend to which the secondary variable has been sampled additionally to the primary. Is there any difference between ordinary kriging and ordinary cokriging in the situation where all observations of the primary and secondary variable are located at the same locations? Will ordinary cokriging have in that situation any advantage over ordinary kriging? Thanks in advantage, De Boever Maarten. -- ir. Maarten De Boever Research Group Soil Spatial Inventory Techniques (ORBIT) Department Soil Management and Soil Care Faculty of Bioscience Engineering Ghent University Coupure 653, 9000 Gent, Belgium Tel. + 32 (0)9 264 6042 Fax + 32 (0)9 264 6247 e-mail : [EMAIL PROTECTED] http://www.soilman.ugent.be/orbit + + To post a message to the list, send it to ai-geostats@jrc.it + 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/ + + To post a message to the list, send it to ai-geostats@jrc.it + 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/
