Data Types

FPL defines structured types that hold NetCDF grid data, coordinates, metadata, and attributes in a single variable.

Naming Convention

Type names follow the pattern:

nc{D}d_{type}_{coord}[_t{ttype}][_l{ltype}]

Segment	Values	Meaning
D	2, 3, 4	Number of dimensions
type	byte, short, int, float, double	Data precision
coord	llf, lld	Coordinate precision (float / double)
ttype	ti, tf, td	Time dimension type (int / float / double) — 3D/4D only
ltype	li, lf	Level dimension type (int / float) — 4D only

Examples

Type Name	Description
nc2d_float_llf	2D float grid, float coordinates
nc3d_int_lld_ti	3D integer grid, double coordinates, integer time
nc4d_double_llf_tf_lf	4D double grid, float coords, float time, float levels

2D Type Fields

type :: nc2d_{type}_{coord}
  sequence
  character(len=100) :: varname      ! Variable name
  character(len=100) :: lonname      ! Longitude dimension name
  character(len=100) :: latname      ! Latitude dimension name
  character(len=100) :: long_name    ! Descriptive name
  character(len=100) :: varunits     ! Variable units
  character(len=100) :: lonunits     ! Longitude units
  character(len=100) :: latunits     ! Latitude units

  integer :: nlons, nlats            ! Grid dimensions
  integer :: ndims, vartype          ! Number of dims, NetCDF type code
  {type} :: FillValue                ! Missing data marker

  real({coord}), allocatable :: longitudes(:)   ! Longitude array
  real({coord}), allocatable :: latitudes(:)    ! Latitude array
  {type}, allocatable :: ncdata(:,:)            ! Data array (lon × lat)
end type

3D Type Fields

Adds to 2D fields:

Field	Type	Description
timename	character(100)	Time dimension name
timeunits	character(100)	Time units
ntimes	integer	Number of time steps
times(:)	integer/real	Time coordinate array
ncdata(:,:,:)	{type}	Data array (lon × lat × time)

4D Type Fields

Adds to 3D fields:

Field	Type	Description
levelname	character(100)	Level dimension name
levelunits	character(100)	Level units
nlevels	integer	Number of levels
levels(:)	integer/real	Level coordinate array
ncdata(:,:,:,:)	{type}	Data array (lon × lat × time × level)

Internal Metadata Fields

All types also contain these internal fields used by the I/O routines:

Field	Type	Description
dimname(:)	character(100)	Dimension names (allocatable)
dimunits(:)	character(100)	Dimension units (allocatable)
dimid(:)	integer	NetCDF dimension IDs
dimsize(:)	integer	Dimension sizes
varids(:)	integer	NetCDF variable IDs
dims(D)	integer	Array of dimension sizes

Total Types

FPL provides 5 data types × 2 coordinate precisions = 10 variants per dimension class:

Class	Variants	Total
2D	5 types × 2 coords	10
3D	5 types × 2 coords × 3 time types	30
4D	5 types × 2 coords × 3 time types × 2 level types	60
Grand Total		100 types