[SciPy-User] help in starting with netCDF
Timmie
timmichelsen at gmx-topmail.de
Tue Aug 10 11:41:32 EDT 2010
Hello,
I am finally diving into netCDF.
I need some assistance in defining coordinate variables such as
"humidity:coordinates"
May someone please help me creating a python file with this CDL:
dimensions:
station = 10 ; // measurement locations
pressure = 11 ; // pressure levels
time = UNLIMITED ;
variables:
float humidity(time,pressure,station) ;
humidity:long_name = "specific humidity" ;
humidity:coordinates = "lat lon" ;
double time(time) ;
time:long_name = "time of measurement" ;
time:units = "days since 1970-01-01 00:00:00" ;
float lon(station) ;
lon:long_name = "station longitude";
lon:units = "degrees_east";
float lat(station) ;
lat:long_name = "station latitude" ;
lat:units = "degrees_north" ;
float pressure(pressure) ;
pressure:long_name = "pressure" ;
pressure:units = "hPa" ;
Source: http://cf-pcmdi.llnl.gov/documents/cf-conventions/1.4/ch05s04.html#id3141969
Here is my start:
from netCDF4 import Dataset
ncfile = Dataset('station_data.nc','w')
ncfile.createDimension('station', 10)
ncfile.createDimension('pressure', 11)
ncfile.createDimension('time',None)
hum = ncfile.createVariable('hum',dtype('float32'),
('lat', 'lon', 'time', 'pressure', 'station'))
hum.long_name = 'specific humidity'
timevar = ncfile.createVariable('time',dtype('float32'), ('time'))
timevar.long_name = 'time of measurement'
timevar.units = 'days since 1970-01-01 00:00:00'
lon = ncfile.createVariable('lon',dtype('float32'), ('station'))
lon.long_name = 'station longitude'
lon.units = 'degrees_east'
lat = ncfile.createVariable('lat',dtype('float32'), ('station'))
lat.long_name = 'station latitude'
lat.units = 'degrees_west'
pressure = ncfile.createVariable('pressure',dtype('float32'), ('pressure'))
pressure.long_name = 'pressure'
pressure.units = 'hPa'
ncfile.close()
I also have the following question:
Is it possible with some python library to convert cdl or ncml into a nc file?
I would like to use this NC file in order to stort 4D data: network of
measurements stations with a corresponding time series for each station.
Thanks a lot in advance,
Timmie
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