Enrico, we have built an online system to perform this as part of the INTAMAP project - you can try this here:
http://intamap.geo.uu.nl/~jon/intamap/tryIntamapj.php If you paste in observations with Gaussian errors (I assume the +/- means one or two standard deviations - I would check this!) in the form x, y, value, stddev then our interpolation method (called psgp, which will shortly be released as an R and C++ library too) will provide a prediction of the mean and variance using a maximum likelihood Gaussian process method. The interface on that web page should allow you to try out the system very simply and the associated web site has details for more interactive ways of using the service, or installing the system on your own machine. If you want to have a quick look I suggest using the OMI NO2 data set which contains error estimates (this could take a little bit of time depending on the usage of the service!). Note the visualisation is still a little beta, so I would not entirely trust the legends! Further details will be added to the web site in the next few weeks! cheers Dan ------------------------------------------- Dr Dan Cornford Senior Lecturer, Computer Science and NCRG Aston University, Birmingham B4 7ET www: http://wiki.aston.ac.uk/DanCornford/ tel: +44 (0)121 204 3451 mob: 07766344953 ------------------------------------------- ________________________________ From: owner-ai-geost...@jrc.it [mailto:owner-ai-geost...@jrc.it] On Behalf Of Enrico Guastaldi Sent: 28 September 2009 13:55 To: ai-geostats@jrc.it Subject: AI-GEOSTATS: Interpolation of measures with measurement errors Dear list members, I'm looking for some kind of interpolation for values of an environmental variable which has been measured together the measurement errors, for instance a measure is 45ppm +or- 10.7ppm, another one is 10ppm +or- 3ppm, and so on. In practice, measures and measurement errors are two independent variable. I could use some kind of kriging, however I exactly know the magnitude of each error at every sampled location, i.e. the value plus or minus the error gave me by the laboratory. Could anyone tell me what kind of function should I use for handling this problem? It should be nice some R package, of course, but I need to understand the background theory. Thanks in advance, Regards, Enrico Guastaldi
