Re: [netcdfgroup] Using netcdf library to access open dap served data

Roy-
Basically, you want to use the url (including any opendap constraints)
as the path argument to nc_open(). As with any other dataset, you then
need to read the actual data using e.g. nc_vara().

The tricky part is this: in order to see what the metadata is (dimensions
variables, etc), you probably
should use ncdump -h "url+constraint" to see what what the library did
when it translated the dap model to the netcdf-3 model.

One you have that metadata, you can just write your program using that 
information.

=Dennis Heimbigner
 Unidata

p.s. we probably should put some documentation about this.


Roy Mendelssohn - NOAA Federal wrote:
Hi All:

I am still a little confused on how to use opendap from within the netcdf library,  The 
online documentation says I put the URL, including the constraint, into the "open 
file" command ( which will differ by language).  So since I am including the 
constraint into the URL of the open command, is that, and the data is transferred, or is 
is viewed as a virtual datasets and I need to do the usual reads to extract the data?  If 
the latter, is the size (and therefore the relative indexing) based on the virtual 
dataset or the actual one?

I looked in the library examples for a program that did this and didn't find 
it, if there is a test program in there somewhere you can point me to it would 
be much appreciated.

-Roy



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"The contents of this message do not reflect any position of the U.S. Government or 
NOAA."
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Roy Mendelssohn
Supervisory Operations Research Analyst
NOAA/NMFS
Environmental Research Division
Southwest Fisheries Science Center
1352 Lighthouse Avenue
Pacific Grove, CA 93950-2097

e-mail: Roy.Mendelssohn@xxxxxxxx (Note new e-mail address)
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