John,
I happen to know this user ;-) and yes, he was just sloppy on this one. It
might be he didn't notice that "topo" was lacking the coordinates attribute
because he was using IDV. IDV is smart enough that if it finds the
"coordinates" attribute specified for one variable, it uses those for other
variables that have the same dimensions (in this case "j" and "i") yet
don't have the "coordinates" attribute specified. So it sort of cleans up
after sloppy people.
-Rich
Dr. Richard P. Signell rsignell at usgs.gov
U.S. Geological Survey (508) 457-2229
384 Woods Hole Road Fax: (508) 457-2310
Woods Hole, MA 02543-1598
-----cf-metadata-bounces at cgd.ucar.edu wrote: -----
To: CF-metadata <cf-metadata at cgd.ucar.edu>
From: John Caron <caron at unidata.ucar.edu>
Sent by: cf-metadata-bounces at cgd.ucar.edu
Date: 01/26/2005 02:37PM
Subject: [CF-metadata] variable missing "coordinates" attribute
the folllowing file has a variable "topo" that is missing the
"coordinates = lat,lon" that would assign the 2D lat, lon coordinates to
it.
i have been interpreting this strictly, namely that the user is choosing
not to assign, but in fact its more likely that they simply forgot, or
they dont think of topo as a data variable.
note that the time coordinate is assigned automatically because it is a
coordinate variable. thus the set of coordinates are either 1)
implicitly assigned coordinate variables or2) explicitly assigned via
the "coordinates" attribute.
i am adding some heuristics to deal with common errors like below, but i
thought maybe someone might have some thoughts or comments.
netcdf
dods://www.satlab.hawaii.edu/cgi-bin/nph-dods/adria/models/coamps/coamps_wind.nc
{
dimensions:
time = UNLIMITED; // (5808 currently) // (has coord.var)
j = 205;
i = 187;
variables:
double time(time);
:units = "days since 1968-5-23";
:long_name = "modified julian day (ROMS-style)";
float lon(j, i);
:units = "degrees_east";
:long_name = "longitude";
float lat(j, i);
:units = "degrees_north";
:long_name = "latitude";
float topo(j, i);
:units = "m";
:long_name = "land elevation";
float U10(time, j, i);
:long_name = "Eastward wind component";
:units = "m/s";
:scale_factor = 0.001525925; // float
:add_offset = 0.0; // float
:coordinates = "lon lat";
float V10(time, j, i);
:long_name = "Northward wind component";
:units = "m/s";
:scale_factor = 0.001525925; // float
:add_offset = 0.0; // float
:coordinates = "lon lat";
:Conventions = "CF-1.0";
:title = "COAMPS(TM) output from Jim Doyle, NRL/MRY";
:institution = "NATO/SACLANT Undersea Research Centre";
:source = "COAMPS V3.0";
:contact = "Rich Signell (rsignell at usgs.gov), Jim Doyle
(doyle at nrlmry.navy.mil)";
:comment = "Hourly COAMPS reanalysis fields were obtained from Jim
Doyle. Continuous hourly fields were constructed by extracting hours
02-13 from the
twice daily hindcast initializations at 0000 UTC and 1200 UTC. Thus no
analysis time data
was used, the rationale being that some spin-up time is desirable. The
data were then
compacted from float to short integers to save space (for those
parameters that do not require
a large dynamic range).";
:history = "Fri Feb 13 06:27:51 2004: ncrcat -O coamps_wind.200209.nc
coamps_wind.200210.nc coamps_wind.200211.nc coamps_wind.200212.nc
coamps_wind.200301.nc coamps_wind.200302.nc coamps_wind.200303.nc
coamps_wind.200304.nc coamps_wind.nc
Fri Feb 13 05:51:54 2004: ncatted -O -a contact,global,o,c,Rich Signell
(rsignell at usgs.gov), Jim Doyle (doyle at nrlmry.navy.mil)
coamps_wind.200209.nc";
}
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Received on Wed Jan 26 2005 - 14:01:23 GMT
