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C This is part of the netCDF package.
C Copyright 2006 University Corporation for Atmospheric Research/Unidata.
C See COPYRIGHT file for conditions of use.
C This example writes some surface pressure and temperatures. It is
C intended to illustrate the use of the netCDF fortran 77 API. The
C companion program sfc_pres_temp_rd.f shows how to read the netCDF
C data file created by this program.
C This program is part of the netCDF tutorial:
C http://www.unidata.ucar.edu/software/netcdf/docs/netcdf-tutorial
C Full documentation of the netCDF Fortran 77 API can be found at:
C http://www.unidata.ucar.edu/software/netcdf/docs/netcdf-f77
C $Id: sfc_pres_temp_wr.f,v 1.10 2007/02/14 20:59:20 ed Exp $
program sfc_pres_temp_wr
implicit none
include 'netcdf.inc'
C This is the name of the data file we will create.
character*(*) FILE_NAME
parameter (FILE_NAME='sfc_pres_temp.nc')
integer ncid
C We are writing 2D data, a 12 x 6 lon-lat grid. We will need two
C netCDF dimensions.
integer NDIMS
parameter (NDIMS=2)
integer NLATS, NLONS
parameter (NLATS = 6, NLONS = 12)
character*(*) LAT_NAME, LON_NAME
parameter (LAT_NAME='latitude', LON_NAME='longitude')
integer lon_dimid, lat_dimid
C In addition to the latitude and longitude dimensions, we will also
C create latitude and longitude netCDF variables which will hold the
C actual latitudes and longitudes. Since they hold data about the
C coordinate system, the netCDF term for these is: "coordinate
C variables."
real lats(NLATS), lons(NLONS)
integer lat_varid, lon_varid
real START_LAT, START_LON
parameter (START_LAT = 25.0, START_LON = -125.0)
C We will write surface temperature and pressure fields.
character*(*) PRES_NAME, TEMP_NAME
parameter (PRES_NAME='pressure')
parameter (TEMP_NAME='temperature')
integer pres_varid, temp_varid
integer dimids(NDIMS)
C It's good practice for each variable to carry a "units" attribute.
character*(*) UNITS
parameter (UNITS = 'units')
character*(*) PRES_UNITS, TEMP_UNITS, LAT_UNITS, LON_UNITS
parameter (PRES_UNITS = 'hPa', TEMP_UNITS = 'celsius')
parameter (LAT_UNITS = 'degrees_north')
parameter (LON_UNITS = 'degrees_east')
C We will create some pressure and temperature data to write out.
real pres_out(NLONS, NLATS), temp_out(NLONS, NLATS)
real SAMPLE_PRESSURE
parameter (SAMPLE_PRESSURE = 900.0)
real SAMPLE_TEMP
parameter (SAMPLE_TEMP = 9.0)
C Loop indices.
integer lat, lon
C Error handling.
integer retval
C Create pretend data. If this were not an example program, we would
C have some real data to write, for example, model output.
do lat = 1, NLATS
lats(lat) = START_LAT + (lat - 1) * 5.0
end do
do lon = 1, NLONS
lons(lon) = START_LON + (lon - 1) * 5.0
end do
do lon = 1, NLONS
do lat = 1, NLATS
pres_out(lon, lat) = SAMPLE_PRESSURE +
+ (lon - 1) * NLATS + (lat - 1)
temp_out(lon, lat) = SAMPLE_TEMP +
+ .25 * ((lon - 1) * NLATS + (lat - 1))
end do
end do
C Create the file.
retval = nf_create(FILE_NAME, nf_clobber, ncid)
if (retval .ne. nf_noerr) call handle_err(retval)
C Define the dimensions.
retval = nf_def_dim(ncid, LAT_NAME, NLATS, lat_dimid)
if (retval .ne. nf_noerr) call handle_err(retval)
retval = nf_def_dim(ncid, LON_NAME, NLONS, lon_dimid)
if (retval .ne. nf_noerr) call handle_err(retval)
C Define the coordinate variables. They will hold the coordinate
C information, that is, the latitudes and longitudes. A varid is
C returned for each.
retval = nf_def_var(ncid, LAT_NAME, NF_REAL, 1, lat_dimid,
+ lat_varid)
if (retval .ne. nf_noerr) call handle_err(retval)
retval = nf_def_var(ncid, LON_NAME, NF_REAL, 1, lon_dimid,
+ lon_varid)
if (retval .ne. nf_noerr) call handle_err(retval)
C Assign units attributes to coordinate var data. This attaches a
C text attribute to each of the coordinate variables, containing the
C units.
retval = nf_put_att_text(ncid, lat_varid, UNITS, len(LAT_UNITS),
+ LAT_UNITS)
if (retval .ne. nf_noerr) call handle_err(retval)
retval = nf_put_att_text(ncid, lon_varid, UNITS, len(LON_UNITS),
+ LON_UNITS)
if (retval .ne. nf_noerr) call handle_err(retval)
C Define the netCDF variables. The dimids array is used to pass the
C dimids of the dimensions of the netCDF variables.
dimids(1) = lon_dimid
dimids(2) = lat_dimid
retval = nf_def_var(ncid, PRES_NAME, NF_REAL, NDIMS, dimids,
+ pres_varid)
if (retval .ne. nf_noerr) call handle_err(retval)
retval = nf_def_var(ncid, TEMP_NAME, NF_REAL, NDIMS, dimids,
+ temp_varid)
if (retval .ne. nf_noerr) call handle_err(retval)
C Assign units attributes to the pressure and temperature netCDF
C variables.
retval = nf_put_att_text(ncid, pres_varid, UNITS, len(PRES_UNITS),
+ PRES_UNITS)
if (retval .ne. nf_noerr) call handle_err(retval)
retval = nf_put_att_text(ncid, temp_varid, UNITS, len(TEMP_UNITS),
+ TEMP_UNITS)
if (retval .ne. nf_noerr) call handle_err(retval)
C End define mode.
retval = nf_enddef(ncid)
if (retval .ne. nf_noerr) call handle_err(retval)
C Write the coordinate variable data. This will put the latitudes
C and longitudes of our data grid into the netCDF file.
retval = nf_put_var_real(ncid, lat_varid, lats)
if (retval .ne. nf_noerr) call handle_err(retval)
retval = nf_put_var_real(ncid, lon_varid, lons)
if (retval .ne. nf_noerr) call handle_err(retval)
C Write the pretend data. This will write our surface pressure and
C surface temperature data. The arrays of data are the same size as
C the netCDF variables we have defined.
retval = nf_put_var_real(ncid, pres_varid, pres_out)
if (retval .ne. nf_noerr) call handle_err(retval)
retval = nf_put_var_real(ncid, temp_varid, temp_out)
if (retval .ne. nf_noerr) call handle_err(retval)
C Close the file.
retval = nf_close(ncid)
if (retval .ne. nf_noerr) call handle_err(retval)
C If we got this far, everything worked as expected. Yipee!
print *,'*** SUCCESS writing example file sfc_pres_temp.nc!'
end
subroutine handle_err(errcode)
implicit none
include 'netcdf.inc'
integer errcode
print *, 'Error: ', nf_strerror(errcode)
stop 2
end
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