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Hi Ken,
This is off-topic, but I recommend you also start adding a CF "calendar"
attribute, such as
time:calendar = "julian";
to files like this. The current netCDF snapshot distribution supports a
"-t" option that displays times in a human readable ISO-8601 form, so if
you run "ncdump -t" on the netCDF file corresponding to the CDL you've
given, the output for the time variable is:
time = "2005-08-18 18", "2005-08-19", "2005-08-19 06", "2005-08-19 12",
"2005-08-19 18", "2005-08-20", "2005-08-20 06", "2005-08-20 12",
"2005-08-20 18", "2005-08-21", "2005-08-21 06", "2005-08-21 12",
"2005-08-21 18", "2005-08-22", "2005-08-22 06", "2005-08-22 12",
"2005-08-22 18", "2005-08-23", "2005-08-23 06", "2005-08-23 12",
"2005-08-23 18", "2005-08-24", "2005-08-24 06", "2005-08-24 12",
"2005-08-24 18", "2005-08-25", "2005-08-25 06", "2005-08-25 12",
"2005-08-25 18", "2005-08-26", "2005-08-26 06", "2005-08-26 12",
"2005-08-26 18", "2005-08-27", "2005-08-21 12", "2005-08-21 18",
"2005-08-22", "2005-08-22 06", "2005-08-22 12" ;
instead of
> time = 53601.75, 53602, 53602.25, 53602.5, 53602.75, 53603, 53603.25,
> 53603.5, 53603.75, 53604, 53604.25, 53604.5, 53604.75, 53605, 53605.25,
> 53605.5, 53605.75, 53606, 53606.25, 53606.5, 53606.75, 53607, 53607.25,
> 53607.5, 53607.75, 53608, 53608.25, 53608.5, 53608.75, 53609, 53609.25,
> 53609.5, 53609.75, 53610, 53604.5, 53604.75, 53605, 53605.25, 53605.5 ;
This is a new capability that still has limitations and probably bugs,
but we plan to include it in the next release. I would be curious if
the Julian calendar as defined in the CF conventions corresponds to what
you intended with the
time:long_name = "Modified Julian Day" ;
In other words, have we got the dates and times above right?
--Russ
> I'm working on writing tropical storm track data in netCDF.
> I think they should be written as CDM trajectories, but am unsure how to
> have ToolsUI recognize them as trajectories.
> I've attached below the CDL for a simple set of two storms. What do I
> need to change to have ToolsUI recognize them as trajectories??
>
> Thanks in advance-
> -Ken
>
> netcdf one_file {
> dimensions:
> storm = 2 ;
> record = UNLIMITED ; // (39 currently)
> variables:
> short storm(storm) ;
> int firstObs(storm) ;
> short numObs(storm) ;
> short trajectoryIndex(record) ;
> float time(record) ;
> time:long_name = "Modified Julian Day" ;
> time:units = "days since 1858-11-17 00:00:00" ;
> float lat(record) ;
> lat:long_name = "Storm center latitude" ;
> lat:units = "degrees_north" ;
> float lon(record) ;
> lon:long_name = "Storm center longitude" ;
> lon:units = "degrees_east" ;
> short wind(record) ;
> wind:long_name = "Minimum Central Pressure" ;
> wind:units = "mb" ;
> short pres(record) ;
>
> // global attributes:
> :cdm_datatype = "Trajectory" ;
> :trajectoryDimension = "storm" ;
> :Conventions = "Unidata Observation Dataset v1.0" ;
> data:
>
> storm = 0, 1 ;
>
> firstObs = 0, 34 ;
>
> numObs = 34, 5 ;
>
> trajectoryIndex = 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
> 16,
> 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33,
> 0, 1,
> 2, 3, 4 ;
>
> time = 53601.75, 53602, 53602.25, 53602.5, 53602.75, 53603, 53603.25,
> 53603.5, 53603.75, 53604, 53604.25, 53604.5, 53604.75, 53605, 53605.25,
> 53605.5, 53605.75, 53606, 53606.25, 53606.5, 53606.75, 53607, 53607.25,
> 53607.5, 53607.75, 53608, 53608.25, 53608.5, 53608.75, 53609, 53609.25,
> 53609.5, 53609.75, 53610, 53604.5, 53604.75, 53605, 53605.25, 53605.5 ;
>
> lat = 13.3, 13.5, 13.6, 13.8, 14, 14.3, 14.9, 15.7, 16.5, 17.2, 17.8,
> 18.3,
> 18.6, 18.9, 19.2, 19.6, 20, 20.4, 20.9, 21.4, 22, 22.7, 23.3, 23.9,
> 24.3,
> 24.7, 25, 25.3, 25.6, 25.7, 25.7, 25.6, 25.5, 25.5, 19.4, 19.6, 19.7,
> 19.7, 19.7 ;
>
> lon = -96.6, -98.2, -99.8, -101.3, -102.5, -103.7, -104.7, -105.6, -107.1,
> -108.5, -110, -111.5, -112.3, -113.2, -114.1, -114.9, -115.6, -116.1,
> -116.7, -117.2, -117.7, -118.4, -119.1, -119.9, -120.7, -121.6, -122.6,
> -123.6, -124.6, -125.5, -126.5, -127.5, -128.5, -129.4, -94.5, -95,
> -95.7, -96.7, -97.7 ;
>
> wind = 22, 26, 35, 44, 48, 57, 62, 62, 66, 79, 79, 79, 75, 70, 66, 62, 62,
> 57, 57, 57, 48, 40, 35, 31, 26, 22, 22, 22, 22, 22, 22, 22, 22, 22, 26,
> 31, 40, 31, 22 ;
>
> pres = 1007, 1006, 1002, 997, 994, 987, 983, 981, 979, 972, 970, 972, 974,
> 976, 981, 983, 985, 986, 987, 990, 994, 998, 1000, 1002, 1003, 1004,
> 1005, 1006, 1007, 1008, 1008, 1009, 1009, 1010, 1006, 1004, 1001, 1002,
> 1005 ;
> }
>
> --
> Ken Knapp
> Remote Sensing and Applications Division
> National Climatic Data Center
> 151 Patton Ave
> Asheville, NC 28801
> 828-271-4339 (voice) 828-271-4328 (fax)
> http://www.ncdc.noaa.gov/
> http://www.ncdc.noaa.gov/oa/rsad/isccpb1/
>
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