[netCDF #DAG-557381]: ncdump -t interprets attributes of inappropriate variables (needs to check for origin in units)

Hi Hoop,

Thanks for reporting this bug  with ncdump -t!

I'll try to get a fix for it in the next release.

--Russ

> Unidata support personnel,
> 
> Here is the output from version 4.2 ncdump -th on the file:
> 
> ftp://ftp.cdc.noaa.gov/Datasets/icoads/2degree/enh/air.mean_day.nc
> http://www.esrl.noaa.gov/psd/thredds/dodsC/Datasets/icoads/2degree/enh/air.mean_day.nc
> 
> netcdf air.mean_day {
> dimensions:
> time = UNLIMITED ; // (2549 currently)
> lat = 90 ;
> lon = 180 ;
> variables:
> float lat(lat) ;
> lat:long_name = "Latitude" ;
> lat:units = "degrees_north" ;
> lat:actual_range = 89.f, -89.f ;
> lat:standard_name = "latitude" ;
> lat:axis = "Y" ;
> float lon(lon) ;
> lon:long_name = "Longitude" ;
> lon:units = "degrees_east" ;
> lon:actual_range = 1.f, 359.f ;
> lon:standard_name = "longitude" ;
> lon:axis = "X" ;
> double time(time) ;
> time:units = "days since 1-1-1 00:00:0.0" ;
> time:long_name = "Time" ;
> time:delta_t = "0000-01-00 00:00:00" ;
> time:avg_period = "0000-01-00 00:00:00" ;
> time:actual_range = 657073., 734625. ; // "1800-01-01",
> "2012-05-01"
> time:standard_name = "time" ;
> time:axis = "T" ;
> short air(time, lat, lon) ;
> air:unpacked_valid_range = 1.f, 31.f ; // "1979-01-02",
> "1979-02-01"
> air:actual_range = 2.f, 30.f ; // "1979-01-03", "1979-01-31"
> air:units = "days" ;
> air:precision = 0s ; // "1979-01-01"
> air:missing_value = 32766s ; // "2068-09-16"
> air:_FillValue = 32766s ; // "2068-09-16"
> air:long_name = "Air Temperature Monthly Mean_day at Surface" ;
> air:dataset = "ICOADS 2-degree Enhanced" ;
> air:var_desc = "Air Temperature" ;
> air:level_desc = "Surface" ;
> air:statistic = "Mean Day of Month of Observations" ;
> air:parent_stat = "Individual Obs" ;
> air:add_offset = 32767.f ; // "2068-09-17"
> air:scale_factor = 1.f ; // "1979-01-02"
> air:valid_range = -32766s, -32736s ; // "1889-04-16", "1889-05-16"
> 
> // global attributes:
> :title = "ICOADS 2-degree Enhanced" ;
> :history = "Release 2.5.2" ;
> :Conventions = "COARDS" ;
> :references =
> "http://www.esrl.noaa.gov/psd/data/gridded/data.coads.2deg.html"; ;
> }
> 
> 
> The -t flag is causing inappropriate interpretations in the added comments for
> the data variable "air", because the units string is a time unit.  The
> criteria in CF says that the unit must also have an origin.  I know that
> ncdump uses CDTime rather than Udunits, but in the Udunits package, there is
> a single call to determine if a time unit has an origin.  I hope this is also
> true for CDTime.
> 
> -Hoop
> 
> 

Russ Rew                                         UCAR Unidata Program
address@hidden                      http://www.unidata.ucar.edu



Ticket Details
===================
Ticket ID: DAG-557381
Department: Support netCDF
Priority: Normal
Status: Closed