[R-sig-Geo] problem reading netcdf file with readGDAL: "no bands in dataset"

[Michael Sumner]

See this page for more information about the GDAL approach to NetCDF:
http://www.gdal.org/frmt_netcdf.html

If you can construct the subdataset name correctly then readGDAL
should be able to return the given variable, as a single band
SpatialGridDataFrame.



On Thu, Nov 26, 2009 at 7:27 AM, Michael Sumner <mdsumner at gmail.com> wrote:
> There are a number of reasons why GDAL might not be able to read data
> from NetCDF, although it might appear to get some metadata upfront.
> The 512x512 thing is a default, and to me means that there are
> multiple variables in the file, and GDAL requires direct reference to
> only one of them as a "subdataset". The syntax is something like this:
>
> NETCDF:"/path/to/filename.nc":varname
>
> If you use gdalinfo at the command line it will tell you the
> subdataset strings you can use - the rgdal bindings don't reconstruct
> the output that that utility gives you.
>
> Cheers, Mike.
>
> On Thu, Nov 26, 2009 at 12:34 AM, ElenaC <E.Couce.07 at bristol.ac.uk> wrote:
>>
>> Hi all,
>>
>> I'm trying to open a netcdf file using the rgdal library, but readGDAL and
>> GDALinfo don't seem to be able to correctly access the information in the
>> file. It is probably a stupid mistake because I don't understand what I'm
>> doing, but I have already spent a long time trying to sort it out and I
>> could really use some help with it.
>>
>> When I try readGDAL, it fails with the error that there are "no bands in
>> dataset". This is the output I get from GDALinfo:
>>
>>> GDALinfo(fname)
>> rows        512
>> columns     512
>> bands       0
>> origin.x        0
>> origin.y        1
>> res.x       1
>> res.y       1
>> oblique.x   0
>> oblique.y   0
>> driver      netCDF
>> projection  NA
>>
>> Warning messages:
>> 1: In dim(x) : no bands in dataset
>> 2: In GDALinfo(fname) : no bands in dataset
>>
>>
>>
>> But from opening the file with Panoply, it seems it actually contains four
>> variables, two of them 360*180 matrices with the geographical info I'm
>> trying to access (global data with 1 degree spatial resolution), and the two
>> others called "lat" and "lon" with the latitude and longitude values.
>>
>> I don't understand why GDALinfo is telling me that the file has 512 rows and
>> 512 columns and that there are "no bands". What can I do to access the
>> variables I want?
>>
>> Any help would be greatly appreciated!
>> Elena
>> --
>> View this message in context: http://n2.nabble.com/problem-reading-netcdf-file-with-readGDAL-no-bands-in-dataset-tp4064987p4064987.html
>> Sent from the R-sig-geo mailing list archive at Nabble.com.
>>
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>