[R] Rate of Reading into R from net

Ivan Krylov kry|ov@r00t @end|ng |rom gm@||@com
Mon Nov 14 14:25:31 CET 2022


В Mon, 14 Nov 2022 13:04:31 +0000
Nick Wray <nickmwray using gmail.com> пишет:

> nc_data<-nc_open("
> https://catalogue.ceh.ac.uk/datastore/eidchub/2ab15bf0-ad08-415c-ba64-831168be7293/precip/chess-met_precip_gb_1km_daily_19610301-19610331.nc
> ")
> 
> However, when I run this I don't get an error message but R just sits
> there with the little red circle (at least 30 minutes for the 90Mb
> files)

Not sure why it just sits there, but looking at the package source
code, I can see that ncdf4::nc_open eventually forwards its arguments
to the nc_open function from the netcdf library:

https://github.com/cran/ncdf4/blob/1.19/R/ncdf4.R#L568
https://github.com/cran/ncdf4/blob/1.19/src/ncdf.c#L862
https://docs.unidata.ucar.edu/netcdf-c/current/group__datasets.html#gaccbdb128a1640e204831256dbbc24d3e

netcdf does support some form of remote file access, but only
OPeNDAP-compatible URLs are supposed to work. Your links ask me to log
in, which may mean that they won't work with netcdf. It might be easier
to use one of the R packages that let you work with libcurl and give
them the cookies from your browser in order to download the files
first, then access them.

See also: https://stackoverflow.com/a/70368135

What does ncdump say about these URLs?

-- 
Best regards,
Ivan

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