[R-sig-Geo] Distances in geoR package

[giovanna jona lasinio]

Dear all, this may be a stupid question, but I wasn't able to find an
answer in the FAQ and in the mail archive.
I have a huge amount of  data, 644 sites for 30 different  times, which
coordinates are expressed in decimal longitude and latitude, I'd like to
simply compute the empirical variogram and use "variofit" to estimate
variogram's parameters for each time. The "variog" function uses
euclidean distances and then it is not appropriate for lon-lat
coordinate. Is there any way to change the distance type in "variog"? Or
which information are necessary to "variofit" in order to estimate
variogram's parameters?

Thanks for any help
Giovanna Jona Lasinio