problem reading netcdf file with readGDAL: "no bands in dataset"

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
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