Recipe: Fortran program as OPeNDAP client: Difference between revisions
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== Program to read downloaded nc4 file == | == Program to read downloaded nc4 file == | ||
Download the collection inst01hr_3d_T_Cv for 2006-Sep-18/0900z as described [[G5NR Data Access Guide#ftp (global data)|here]]. The downloaded file is <code>c1440_NR.inst01hr_3d_T_Cv.20060918_0900z.nc4</code>. The program to read this file is | |||
<nowiki> | <nowiki> | ||
Revision as of 07:58, 27 October 2014
Back to G5NR Data Access Guide.
First, we ensure that out NetCDF-4 library has been built with Fortran, HDF5 and OPeNDAP support. All three queries
> nc-config --has-f90 > nc-config --has-hdf5 > nc-config --has-dap
should return yes.
Program to read downloaded nc4 file
Download the collection inst01hr_3d_T_Cv for 2006-Sep-18/0900z as described here. The downloaded file is c1440_NR.inst01hr_3d_T_Cv.20060918_0900z.nc4. The program to read this file is
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, allocatable :: T(:,:,:,:)
! Miscellaneous
! -------------
integer :: ierr
integer :: im, jm, lm
integer :: ncid, varid
integer :: start(4), count(4)
! file name and dimensions
! ------------------------
im = 720
jm = 361
lm = 72
T_file = "c1440_NR.inst01hr_3d_T_Cv.20060918_0900z.nc4"
! 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")
! Print min/max of arrays
! -----------------------
write(*,*)'T: ', maxval(T),minval(T)
deallocate(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
Compile and run
The above code, g5nr_reader.f90 is compiled as
gfortran