[R] Problem downloading and opening netcdf file

[Prof Brian Ripley]

On Wed, 17 Nov 2010, Barry Rowlingson wrote:

> On Wed, Nov 17, 2010 at 2:54 PM, D Kelly O'Day <koday at processtrends.com> wrote:
>>
>> I am trying to download and open an on-line netcdf file.
>>
>> I'm using Windows XP and R 2.11.1
>>
>> Here's my script
>>
>>  library(ncdf)
>>  link <-
>> "http://ibis.grdl.noaa.gov/SAT/SeaLevelRise/slr/slr_sla_gbl_free_all_66.nc"
>>  dest <-  "C:/temp/slr_sla_gbl_free_all_66.nc"
>>  download.file(url=link,destfile=dest)
>>  nc1 <- open.ncdf(dest)
>>
>> The file appears in my C:/temp directory, however I can not open() it, I get
>> this error message:
>>
>>>   nc1 <- open.ncdf(dest)
>> Error in open.ncdf(dest) :
>>  Error in open.ncdf trying to open file C:/temp/slr_sla_gbl_free_all_66.nc
>>>
>>
>> I can manually download and save the netcdf file and then open it. I'd like
>> to be able to automate the download and open process within my script.
>
> Works for me. When you get the file with download.file is it
> identical to when you download it from a web browser? I can only think
> its getting corrupted, or perhaps your download.file isn't going
> through a proxy or something and you're actually saving a proxy error
> message file.

(S)he is using Windows and forgot mode="wb": AFAIK netcdf files are 
binary files.

> Check the length of the saved file: file.info(dest) should help -
> check the 'size' is what you expect. I get 17004 for that example.
>
> Barry
>
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-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
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