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This looks to be (at least mostly) a CF-compliant file. So you can learn about what all those attribute mean here: http://cfconventions.org/ -Chris On Thu, May 21, 2015 at 8:01 AM, Ted Mansell <ted.mansell@xxxxxxxx> wrote: > The information you need is there in the variable information: > > short Wind_U(time, lat, lon) ; > Wind_U:long_name = "Wind U Component" ; > Wind_U:units = "m/s" ; > Wind_U:scale_factor = 0.01f ; > Wind_U:valid_range = -100s, 100s ; > Wind_U:missing_value = -9999s ; > Wind_U:_FillValue = -9999s ; > Wind_U:coordinate = "lon lat" ; > > So the values are in m/s but need a scale factor of 0.01 applied because > it is stored as a short integer rather than a float. Thus 155 is 1.55 m/s . > > As for the ordering, these are in the C convention (opposite of Fortran) > 'time' is the slowest index, whereas 'lon' is stride one. [In the Fortran > interface, the arrays are automatically switched to (lon, lat, time)] > > Thus: > > Wind_U(time=0, lat=-90, lon=0) = 155 -> 1.55 m/s > Wind_U(time=0, lat=-90, lon=0.5) = 158 -> 1.58 m/s > Wind_U(time=0, lat=-90, lon=1.0) = 161 -> 1.61 m/s > > etc. > > -- Ted > __________________________________________________________ > | Edward Mansell <ted.mansell@xxxxxxxx> > | National Severe Storms Laboratory > |-------------------------------------------------------------- > | "The contents of this message are mine personally and > | do not reflect any position of the U.S. Government or NOAA." > |-------------------------------------------------------------- > > > I suggest getting a viewing tool like ncview to peruse the data > graphically. > > On May 20, 2015, at 9:58 PM, 동희 <gksgg@xxxxxxxxx> wrote: > > > Dear NetCDF suppot team > > > > > > Hello > > > > I am DH from Korea. > > > > I am going to use netcdf file soon to get the weather information at my > company. > > > > But the problem is I am the first one in my company so don't know how to > interpret the nc file. > > > > (I can just convert to txt file with ncdump, and read the letters...) > > > > > > below is the netcdf file which I should interpret...(it contains global > wind information) > > > > > > > ======================================================================================== > > > > netcdf GFS20150520 { > > dimensions: > > lon = 720 ; > > lat = 361 ; > > time = UNLIMITED ; // (57 currently) > > variables: > > float lat(lat) ; > > lat:long_name = "Latitude" ; > > lat:units = "degrees_north" ; > > lat:missing_value = -99999.f ; > > lat:_FillValue = -99999.f ; > > float lon(lon) ; > > lon:long_name = "Longitude" ; > > lon:units = "degrees_east" ; > > lon:missing_value = -99999.f ; > > lon:_FillValue = -99999.f ; > > int time(time) ; > > time:long_name = "forecast time" ; > > time:units = "minutes since 2015-05-20 00:00" ; > > time:standard_name = "time" ; > > time:reference = "UTC" ; > > time:missing_value = -99999 ; > > time:_FillValue = -99999 ; > > short Wind_U(time, lat, lon) ; > > Wind_U:long_name = "Wind U Component" ; > > Wind_U:units = "m/s" ; > > Wind_U:scale_factor = 0.01f ; > > Wind_U:valid_range = -100s, 100s ; > > Wind_U:missing_value = -9999s ; > > Wind_U:_FillValue = -9999s ; > > Wind_U:coordinate = "lon lat" ; > > short Wind_V(time, lat, lon) ; > > Wind_V:long_name = "Wind V Component" ; > > Wind_V:units = "m/s" ; > > Wind_V:scale_factor = 0.01f ; > > Wind_V:valid_range = -100s, 100s ; > > Wind_V:missing_value = -9999s ; > > Wind_V:_FillValue = -9999s ; > > Wind_V:coordinate = "lon lat" ; > > > > // global attributes: > > :title = "Environmental data" ; > > :version = "1.0" ; > > :institution = "ASA" ; > > :Contact = "asa@xxxxxxxxxx" ; > > :source = "NCEP NOAA" ; > > :reference = "Created by DAN_GRIB2NC2 Version 3.0d at 05/20/15 > 18:14:53" ; > > :default_view = "10 meter Wind U, Wind V " ; > > :netcdf_class = "2" ; > > :netcdf_class_description = "Multi point, static, ..." ; > > :time_var = "time" ; > > :lat_var = "Lat" ; > > :lon_var = "lon" ; > > :view_style = "1" ; > > :Conventions = "CF-1.0" ; > > data: > > lat = -90, -89.5, -89, -88.5, -88, -87.5, -87, -86.5, -86, -85.5, -85, > > -84.5, -84, -83.5, -83, -82.5, -82, -81.5, -81, -80.5, -80, -79.5, > -79, > > -78.5, -78, -77.5, -77, -76.5, -76, -75.5, -75, -74.5, -74, -73.5, > -73, > > > > .....(oimt)..... > > > > lon = 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, > > 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, > 15.5, > > 16, 16.5, 17, 17.5, 18, 18.5, 19, 19.5, 20, 20.5, 21, 21.5, 22, > 22.5, 23, > > 23.5, 24, 24.5, 25, 25.5, 26, 26.5, 27, 27.5, 28, 28.5, 29, 29.5, 30, > > > > .....(oimt)..... > > > > time = 0, 180, 360, 540, 720, 900, 1080, 1260, 1440, 1620, 1800, 1980, > 2160, > > 2340, 2520, 2700, 2880, 3060, 3240, 3420, 3600, 3780, 3960, 4140, > 4320, > > 4500, 4680, 4860, 5040, 5220, 5400, 5580, 5760, 5940, 6120, 6300, > 6480, > > 6660, 6840, 7020, 7200, 7380, 7560, 7740, 7920, 8100, 8280, 8460, > 8640, > > 8820, 9000, 9180, 9360, 9540, 9720, 9900, 10080 ; > > > > Wind_U = > > 155, 158, 161, 164, 166, 168, 171, 175, 177, 179, 182, 184, 188, 190, > 192, > > 194, 197, 200, 203, 204, 207, 209, 212, 214, 216, 220, 222, 224, 227, > > 229, 230, 233, 235, 237, 239, 241, 245, 247, 249, 251, 253, 255, 256, > > > > .....(oimt)..... > > > > Wind_V = > > -310, -309, -308, -307, -306, -304, -303, -301, -300, -298, -297, -295, > > -292, -291, -289, -287, -286, -284, -282, -281, -280, -278, -276, > -274, > > -272, -270, -267, -265, -263, -262, -259, -257, -256, -254, -252, > -250, > > -248, -246, -244, -241, -238, -236, -234, -232, -230, -228, -226, > -223, > > > > .....(oimt) > > > > > ======================================================================================== > > > > > > For example, at the above file, the first value of Wind_U, 155 is > simply meaning Wind_U(time, lat, lon)=Wind_U(0, -90, 0) ? > > > > Then what about the second value of Wind_U, 158 ? Is that meaning > Wind_U(0, -90, 0.5) ? or Wind_U(180, -90, 0) ? > > > > I am not sure this is right and I don't know about the order... > > > > > > Please reply me with brief explanation. > > > > Thank you for reading. > > > > > > Best Regards > > > > DH HAN > > > > > > > > _______________________________________________ > > netcdfgroup mailing list > > netcdfgroup@xxxxxxxxxxxxxxxx > > For list information or to unsubscribe, visit: > http://www.unidata.ucar.edu/mailing_lists/ > > > _______________________________________________ > netcdfgroup mailing list > netcdfgroup@xxxxxxxxxxxxxxxx > For list information or to unsubscribe, visit: > http://www.unidata.ucar.edu/mailing_lists/ -- Christopher Barker, Ph.D. Oceanographer Emergency Response Division NOAA/NOS/OR&R (206) 526-6959 voice 7600 Sand Point Way NE (206) 526-6329 fax Seattle, WA 98115 (206) 526-6317 main reception Chris.Barker@xxxxxxxx
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