[R-sig-Geo] getting data from an nc file

[Roy Mendelssohn - NOAA Federal]

Unfortunately you need to register to look at one of those files,  but what I could dig up on the internet suggest the data are on x,y coordinates.  You can find that just giving the command

nc_data 

or for more complete info

str(nc_data)

Also since they say they follow the CF conventions,  so that printout should contain information about the coordinate system.  I can't offhand find the description except a comment somewhere to be careful because of a use fo a different datum.  

HTH,

-Roy

> On Nov 9, 2022, at 2:53 AM, Nick Wray <nickmwray using gmail.com> wrote:
> 
> Hello
> 
> I am trying to get rainfall data from the UK chess-met site
> 
> https://catalogue.ceh.ac.uk/datastore/eidchub/2ab15bf0-ad08-415c-ba64-831168be7293/precip/
> 
> and here there are a large number of nc files eg
> 
> "chess-met_precip_gb_1km_daily_20150101-20150131.nc"
> 
> I’ve found various sources on the net for opening nc files, and getting the
> data but when I try instructions like
> 
> nc_data<-nc_open("chess-met_precip_gb_1km_daily_20150101-20150131.nc")
> 
> lon <- ncvar_get(nc_data, "lon")
> 
> lon
> 
> 
> 
> the code works but all I get is a series of element numbers and no data:
> 
> [,1]     [,2]     [,3]     [,4]     [,5]     [,6]     [,7]     [,8]     [,9]
> [,10]    [,11]    [,12]
> 
>          [,13]    [,14]    [,15]    [,16]    [,17]    [,18]    [,19]
> [,20]    [,21]    [,22]    [,23]    [,24]
> 
> 
> 
> And similarly for latitude
> 
> But if I open the nc file as a raster I get a raster precipitation plot of
> Great Britain, which rather suggests that the lat and long values are in
> there somewhere
> 
> Can anyone help with getting the actual data sets out of an nc file?
> 
> Thanks Nick Wray
> 
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Roy Mendelssohn
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NOAA/NMFS
Environmental Research Division
Southwest Fisheries Science Center
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