module g2grids
!$$$ SUBPROGRAM DOCUMENTATION BLOCK
! . . . .
! MODULE: g2grids
! PRGMMR: Gilbert ORG: W/NP11 DATE: 2004-04-27
!
! ABSTRACT: This Fortran Module allows access to predefined GRIB2 Grid
! Definition Templates stored in a file. The GDTs are represented by
! a predefined number or a character abbreviation.
!
! At the first request, all the grid GDT entries in the file associated
! with input Fortran file unit number, lunit, are read into a linked list
! named gridlist. This list is searched for the requested entry.
!
! Users of this Fortran module should only call routines getgridbynum
! and getgridbyname.
!
! The format of the file scanned by routines in this module is as follows.
! Each line contains one Grid entry containing five fields, each separated
! by a colon, ":". The fields are:
! 1) - predefined grid number
! 2) - Up to an 8 character abbreviation
! 3) - Grid Definition Template number
! 4) - Number of entries in the Grid Definition Template
! 5) - A list of values for each entry in the Grid Definition Template.
!
! As an example, this is the entry for the 1x1 GFS global grid
! 3:gbl_1deg: 0:19: 0 0 0 0 0 0 0 360 181 0 0 90000000 0 48 -90000000 359000000 1000000 1000000 0
!
! Comments can be included in the file by specifying the symbol "#" as the
! first character on the line. These lines are ignored.
!
!
! PROGRAM HISTORY LOG:
! 2004-04-27 Gilbert
!
! USAGE: use g2grids
!
! ATTRIBUTES:
! LANGUAGE: Fortran 90
! MACHINE: IBM SP
!
!$$$
integer,parameter :: MAXTEMP=200
type,private :: g2grid
integer :: grid_num
integer :: gdt_num
integer :: gdt_len
integer,dimension(MAXTEMP) :: gridtmpl
character(len=8) :: cdesc
type(g2grid),pointer :: next
end type g2grid
type(g2grid),pointer,private :: gridlist
integer :: num_grids=0
contains
integer function readgrids(lunit)
!$$$ SUBPROGRAM DOCUMENTATION BLOCK
! . . . .
! SUBPROGRAM: readgrids
! PRGMMR: Gilbert ORG: W/NP11 DATE: 2001-06-28
!
! ABSTRACT: This function reads the list of GDT entries in the file
! associated with fortran unit, lunit. All the entries are stored in a
! linked list called gridlist.
!
! PROGRAM HISTORY LOG:
! 2001-06-28 Gilbert
!
! USAGE: number=readgrids(lunit)
! INPUT ARGUMENT LIST:
! lunit - Fortran unit number associated the the GDT file.
!
! RETURNS: The number of Grid Definition Templates read in.
!
! REMARKS: None
!
! ATTRIBUTES:
! LANGUAGE: Fortran 90
! MACHINE: IBM SP
!
!$$$
integer,intent(in) :: lunit
integer,parameter :: linelen=1280
character(len=8) :: desc
character(len=linelen) :: cline
integer ient,igdtn,igdtmpl(200),igdtlen
integer :: pos1,pos2,pos3,pos4
type(g2grid),pointer :: gtemp
type(g2grid),pointer :: prev
integer count
count=0
! For each line in the file....
DO
! Read line into buffer
!
cline(1:linelen)=' '
read(lunit,end=999,fmt='(a)') cline
!
! Skip line if commented out
!
if (cline(1:1).eq.'#') cycle
!
! find positions of delimiters, ":"
!
pos1=index(cline,':')
cline(pos1:pos1)=';'
pos2=index(cline,':')
cline(pos2:pos2)=';'
pos3=index(cline,':')
cline(pos3:pos3)=';'
pos4=index(cline,':')
if ( pos1.eq.0 .or. pos2.eq.0 .or. pos3.eq.0 .or.
& pos4.eq.0) cycle
!
! Read each of the five fields.
!
read(cline(1:pos1-1),*) ient
read(cline(pos1+1:pos2-1),*) desc
read(cline(pos2+1:pos3-1),*) igdtn
read(cline(pos3+1:pos4-1),*) igdtlen
read(cline(pos4+1:linelen),*) (igdtmpl(j),j=1,igdtlen)
!
! Allocate new type(g2grid) variable to store the GDT
!
allocate(gtemp,stat=iom)
count=count+1
gtemp%grid_num=ient
gtemp%gdt_num=igdtn
gtemp%gdt_len=igdtlen
gtemp%gridtmpl=igdtmpl
gtemp%cdesc=desc
nullify(gtemp%next) ! defines end of linked list.
if ( count .eq. 1 ) then
gridlist => gtemp
else ! make sure previous entry in list
prev%next => gtemp ! points to the new entry,
endif
prev => gtemp
enddo
999 readgrids=count
return
end function
subroutine getgridbynum(lunit,number,igdtn,igdtmpl,iret)
!$$$ SUBPROGRAM DOCUMENTATION BLOCK
! . . . .
! SUBPROGRAM: getgridbynum
! PRGMMR: Gilbert ORG: W/NP11 DATE: 2004-04-26
!
! ABSTRACT: This subroutine searches a file referenced by fortran unit lunit
! for a Grid Definition Template assigned to the requested number.
! The input file format is described at the top of this module.
!
! PROGRAM HISTORY LOG:
! 2004-04-26 Gilbert
!
! USAGE: CALL getgridbynum(lunit,number,igdtn,igdtmpl,iret)
! INPUT ARGUMENT LIST:
! lunit - Unit number of file containing Grid definitions
! number - Grid number of the requested Grid definition
!
! OUTPUT ARGUMENT LIST:
! igdtn - NN, indicating the number of the Grid Definition
! Template 3.NN
! igdtmpl()- An array containing the values of each entry in
! the Grid Definition Template.
! iret - Error return code.
! 0 = no error
! -1 = Undefined Grid number.
! 3 = Could not read any grids from file.
!
! REMARKS: None
!
! ATTRIBUTES:
! LANGUAGE: Fortran 90
! MACHINE: IBM SP
!
!$$$
integer,intent(in) :: lunit,number
integer,intent(out) :: igdtn,igdtmpl(*),iret
type(g2grid),pointer :: tempgrid
iret=0
igdtn=-1
!igdtmpl=0
!
! If no grids in list, try reading them from the file.
!
if ( num_grids .eq. 0 ) then
num_grids=readgrids(lunit)
endif
if ( num_grids .eq. 0 ) then
iret=3 ! problem reading file
return
endif
tempgrid => gridlist
!
! Search through list
!
do while ( associated(tempgrid) )
if ( number .eq. tempgrid%grid_num ) then
igdtn=tempgrid%gdt_num
igdtmpl(1:tempgrid%gdt_len)=
& tempgrid%gridtmpl(1:tempgrid%gdt_len)
return
else
tempgrid => tempgrid%next
endif
enddo
iret=-1
return
end subroutine
subroutine getgridbyname(lunit,name,igdtn,igdtmpl,iret)
!$$$ SUBPROGRAM DOCUMENTATION BLOCK
! . . . .
! SUBPROGRAM: getgridbyname
! PRGMMR: Gilbert ORG: W/NP11 DATE: 2004-04-26
!
! ABSTRACT: This subroutine searches a file referenced by fortran unit lunit
! for a Grid Definition Template assigned to the requested name.
! The input file format is described at the top of this module.
!
! PROGRAM HISTORY LOG:
! 2004-04-26 Gilbert
!
! USAGE: CALL getgridbyname(lunit,name,igdtn,igdtmpl,iret)
! INPUT ARGUMENT LIST:
! lunit - Unit number of file containing Grid definitions
! name - Grid name of the requested Grid definition
!
! OUTPUT ARGUMENT LIST:
! igdtn - NN, indicating the number of the Grid Definition
! Template 3.NN
! igdtmpl()- An array containing the values of each entry in
! the Grid Definition Template.
! iret - Error return code.
! 0 = no error
! -1 = Undefined Grid number.
! 3 = Could not read any grids from file.
!
! REMARKS: None
!
! ATTRIBUTES:
! LANGUAGE: Fortran 90
! MACHINE: IBM SP
!
!$$$
integer,intent(in) :: lunit
character(len=8),intent(in) :: name
integer,intent(out) :: igdtn,igdtmpl(*),iret
type(g2grid),pointer :: tempgrid
iret=0
igdtn=-1
!igdtmpl=0
!
! If no grids in list, try reading them from the file.
!
if ( num_grids .eq. 0 ) then
num_grids=readgrids(lunit)
endif
if ( num_grids .eq. 0 ) then
iret=3 ! problem reading file
return
endif
tempgrid => gridlist
!
! Search through list
!
do while ( associated(tempgrid) )
if ( name .eq. tempgrid%cdesc ) then
igdtn=tempgrid%gdt_num
igdtmpl(1:tempgrid%gdt_len)=
& tempgrid%gridtmpl(1:tempgrid%gdt_len)
return
else
tempgrid => tempgrid%next
endif
enddo
iret=-1
return
end subroutine
end