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[netCDF #JZN-949284]: NC_CHAR coordinates via DAP

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  • Subject: [netCDF #JZN-949284]: NC_CHAR coordinates via DAP
  • Date: Fri, 08 Oct 2010 12:03:41 -0600
Charlie-

The netcdf dap code supports NC_CHAR (modulo bugs, of course).
The transparency issue is tricky. If you mean does the result coming
out of the netcdf dap code look the same as the original .nc file,
then no. The two versions will vary in a number of ways because the mapping
into dap and then out of dap is not completely transparent.

One place in particular where this occurs is when the dap uses its string type
(look at this url in your browser
  http://motherlode.ucar.edu:8080/thredds/dodsC/testdods/in.nc.dds?fl_dmn
)

Since netcdf-3 has no string type, the string is converted to an NC_CHAR array.
The string as stored in that array may be truncated.

There is an additional problem with the data set your provided.
If you do a wget on this url:
  http://motherlode.ucar.edu:8080/thredds/dodsC/testdods/in.nc.dods?fl_dmn
you will get this:
------------------------------
Dataset {
    String fl_dmn[fl_dmn = 3];
} testdods/in.nc;

Data:
Error {
    code = 500;
    message = "[C cannot be cast to [Lopendap.dap.BaseType;";
};
---------------------
So indeed, the data is not readable. That error is coming from the server.
Why that error occurs, I do not know yet.
(Ethan?).

Other, non-string data is apparently readable.

=Dennis Heimbigner
  Unidata


Ticket Details
===================
Ticket ID: JZN-949284
Department: Support netCDF
Priority: Normal
Status: Open