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ET-NCMP / NCMP

Software in R for calculating National Climate Monitoring Products
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Variogram - limited range of functional forms #22

Closed ET-NCMP closed 6 years ago

ET-NCMP commented 7 years ago

A selection of standard variogram functional forms is used, but not all that are known to statistical theory. Any particular reason for the selection?

ET-NCMP commented 7 years ago

These were the most common functional forms in the introductory texts I looked at and did an OK job on fitting my test cases (Europe, USA, Australia, UK, so not anywhere near exhaustive). We could add more, but I don't have a feel for what the gain would be for the extra expense in programming and testing.

ET-NCMP commented 6 years ago

These work reasonably well for a range of cases. At the third face to face meeting, we discussed how "good" the variograms need to be. Obviously, the closer they fit the data, the better, but if the data are very noisy, or the distribution of stations is uneven (as was the case for Morocco with one station in the southern half of the country) then it can be difficult to get a clean fit and some judgement is called for. I'm closing this issue for now as it hasn't been a problem up until now.