Thanks to all that give me some help on the cokriging (Tom, Donald, Susan and Tomislav). By reading Goovaerts (hello thanks for your course in Lisbon last November) paper on precipitation estimation including elevation, I notice that cokriging presents smooth surfaces, but I think this isn't always true. I have tested it for the temperature estimation on Madeira Island, and the maps show clearly a relation with altitude although for Portugal mainland, i could not achieve yet this detail. I have tested the Neural Networks with the same purpose and the resulting map for the annual mean air temperature is very good, it captures fine details and presents variability very well, also the r between observed and estimated values with an independent dataset was very good (0.98). When I decided to test also the cokriging to compare the results I was disapointed, because NN presents a much better map. Now i try to understand why the CK doesn't give results as good as I thought it could give.
I also would like to test kriging with external drift, does anyone know where can I find a friendly and free software to do so, preferencially with a tutorial.
Thanks once again and with my best regards,
�lvaro
Jos� �lvaro Mendes Pimp�o Alves Silva
Ge�grafo - T�cnico de SIG Geographer - GIS Technician
Departamento de Clima e Ambiente Atmosf�rico Climate Department
Instituto de Meteorologia Portuguese Meteorological Institute
Rua C do Aeroporto
1749 - 047 Lisboa
Portugal
Tel: (+351) 218483961
Fax: (+351) 218402370
Email: [EMAIL PROTECTED]
