Example 04 — Generate Grids

Generates 2D, 3D, and 4D grids from a bounding box, fills them with data, and writes to NetCDF.

Source Code

program main
  use fpl
  implicit none

  type(nc2d_double_llf)      :: grid2d
  type(nc3d_int_llf_ti)      :: grid3d
  type(nc4d_float_llf_ti_li) :: grid4d

  integer(kind=intgr) :: i, j, k, l
  real(kind=4) :: Xmin, Ymin, Xmax, Ymax, res
  character(200) :: opath2d, opath3d, opath4d

  opath2d = "database/grid2d.nc"
  opath3d = "database/grid3d.nc"
  opath4d = "database/grid4d.nc"

  ! --- 2D Grid ---
  grid2d%long_name = "My Grid 1 degree"
  grid2d%varname   = "grid"
  grid2d%lonname   = "lon"
  grid2d%latname   = "lat"
  grid2d%varunits  = "dimensionless"
  grid2d%lonunits  = "degrees_east"
  grid2d%latunits  = "degrees_north"
  grid2d%FillValue = -9999

  Xmin = -54.7371;  Ymin = -11.3437
  Xmax = -34.7371;  Ymax = 2.6562
  res  = 0.00833333

  call gengrid(grid2d, Xmin, Ymin, Xmax, Ymax, res)

  !$omp parallel do
  do j = 1, grid2d%nlats
    do i = 1, grid2d%nlons
      grid2d%ncdata(i,j) = cos(grid2d%longitudes(i)) + grid2d%latitudes(j)
    end do
  end do
  !$omp end parallel do

  call writegrid(opath2d, grid2d)

  ! --- 3D Grid ---
  grid3d%long_name = "My Grid 1 degree"
  grid3d%varname   = "grid"
  grid3d%lonname   = "lon"
  grid3d%latname   = "lat"
  grid3d%timename  = "time"
  grid3d%varunits  = "dimensionless"
  grid3d%lonunits  = "degrees_east"
  grid3d%latunits  = "degrees_north"
  grid3d%timeunits = "hour"
  grid3d%ntimes    = 10
  grid3d%FillValue = -9999

  call gengrid(grid3d, -74.73715442059999, -34.343706397220295, -34.73715458059378, 5.6562934427799965, 1.0)

  do i = 1, grid3d%ntimes
    do k = 1, grid3d%nlats
      do j = 1, grid3d%nlons
        grid3d%ncdata(j,k,i) = int(i * (cos(real(j)) * grid3d%longitudes(j) &
                                        + k * grid3d%latitudes(k)))
      end do
    end do
  end do

  call writegrid(opath3d, grid3d)

  ! --- 4D Grid ---
  grid4d%long_name  = "My Grid  ~ 1 degree"
  grid4d%varname    = "grid"
  grid4d%lonname    = "lon"
  grid4d%latname    = "lat"
  grid4d%timename   = "time"
  grid4d%levelname  = "level"
  grid4d%varunits   = "dimensionless"
  grid4d%lonunits   = "degrees_east"
  grid4d%latunits   = "degrees_north"
  grid4d%timeunits  = "hour"
  grid4d%levelunits = "m"
  grid4d%ntimes     = 10
  grid4d%nlevels    = 5
  grid4d%FillValue  = -9999

  call gengrid(grid4d, -74.73715442059999, -34.343706397220295, -34.73715458059378, 5.6562934427799965, 1.0)

  do l = 1, grid4d%nlevels
    do i = 1, grid4d%ntimes
      do k = 1, grid4d%nlats
        do j = 1, grid4d%nlons
          grid4d%ncdata(j,k,i,l) = int((l**3) / i &
            * (cos(real(j)) * grid4d%longitudes(j) + k * grid4d%latitudes(k)))
        end do
      end do
    end do
  end do

  call writegrid(opath4d, grid4d, "database/gridHeader.txt")
end program main

Compile & Run

gfortran -fopenmp -o ex4.out ex4_gengrid.f90 -I/usr/lib64/gfortran/modules/ -lFPL
./ex4.out

Output