Recipe: Fortran program as OPeNDAP client
Program to read downloaded nc4 file
To read a downloaded file in Fortran we need a NetCDF-4 library that has been configured with HDF5 support. Availability of HDF5 support can be checked using the nc-config tool included in the NetCDF-4 package.
> nc_config --has-hdf5
should return the value yes.
program g5nr_reader
use netcdf ! for reading the NR files
implicit none
! File name
! ---------
character(len=256) :: T_file
! Global, 4D array: (lon,lat,lev,time)
! ------------------------------------
real, pointer :: T(:,:,:,:) => null()
! Miscellaneous
! -------------
integer :: ierr
integer :: im, jm, lm
integer :: ncid, varid
integer :: start(4), count(4)
! For now hard code file name and dimensions
! ------------------------------------------
im = 720
jm = 361
lm = 72
T_file = "http://opendap.nccs.nasa.gov:9090/dods/OSSE/GEOS-5.12/BETA9/0.5000_deg/inst/inst01hr_3d_T_Cv"
! Allocate the Global 4-D array with only 1 time level
! ----------------------------------------------------
allocate(T(im,jm,lm,1))
! Hypercube for reading one 1 array for a given time
! -------------------------------------------------
start = (/ 1, 1, 1, 37 /) ! time level 37
count = (/ im, jm, lm, 1 /) ! 1 time level, 3D (lon,lat,lev) array
! Read the data file
! ------------------
write(*,*)'Reading T'
call check( nf90_open(T_file,NF90_NOWRITE,ncid), "opening T file")
call check( nf90_inq_varid(ncid,"t",varid), "getting T varid")
call check( nf90_get_var(ncid,varid,T,start=start,count=count), "reading T")
call check( nf90_close(ncid), "closing T file")
! Orint min/max of arrays
! -----------------------
write(*,*)'T: ', maxval(T),minval(T)
! All done
! --------
contains
subroutine check(status, loc)
integer, intent(in) :: status
character(len=*), intent(in) :: loc
if(status /= NF90_NOERR) then
write (*,*) "Error at ", loc
write (*,*) NF90_STRERROR(status)
end if
end subroutine check
end program g5nr_reader