SUBROUTINE SGRIDS

* SGRIDS is DFILES subroutine revised for state hpgn files

* This subroutine opens the NADCON grids using the state HPGN
* grid files. Only 1 state hpgn file can be open at any one time
* the program loop will take care of using other states in the same
* run - jmb 1/16/92

      IMPLICIT DOUBLE PRECISION (A-H, O-Z)
      IMPLICIT INTEGER (I-N)
*     IMPLICIT UNDEFINED (A-Z)

      INTEGER MXAREA, MXDEF
      PARAMETER (MXAREA = 8, MXDEF = MXAREA, MXSAREA = 3, 
     * MXSDEF = MXSAREA)


      CHARACTER*80 B80
      CHARACTER*65 B65
      CHARACTER*20 B20
      CHARACTER*2  state,tstate(MXSDEF)
      PARAMETER (B20 = '                   ', B80 = B20//B20//B20//B20)
      PARAMETER (B65 = B20//B20//B20//'     ')

      DOUBLE PRECISION XMAX1, XMIN1, YMAX1, YMIN1
      DOUBLE PRECISION DX1, DY1
      INTEGER  ITEMP, NC1
      CHARACTER*80 DUM
      CHARACTER*65 AFILE 
c     CHARACTER*15 DAREAS(MXDEF)
      LOGICAL NOGO, GFLAG

      CHARACTER*15 AREAS
      COMMON /AREAS/ AREAS(MXAREA)

      DOUBLE PRECISION DX, DY, XMAX, XMIN, YMAX, YMIN
      INTEGER NC, NAREA
      COMMON /GDINFO/ DX(MXAREA), DY(MXAREA), XMAX(MXAREA),
     +                XMIN(MXAREA), YMAX(MXAREA), YMIN(MXAREA),
     +                NC(MXAREA), NAREA

      INTEGER LUIN, LUOUT, NOUT, NIN, NAPAR, LUAREA
      COMMON /INOUT/ LUIN, LUOUT, NOUT, NIN, NAPAR, LUAREA(2*MXAREA)

      DATA DUM / B80 /
c the following does not pertain to state grid files

* DFILES contains the default locations (pathname) of the grid files
* without the .las and .los extensions. (For example 'conus' would
* indicate that the conus.las and conus.los grid files are in the
* current working directory.)  The length of each entry in DFILES may
* be up to 65 characters.  DAREAS contains the default names of these
* areas.  The names are used internally in the program and in the
* program output.  They may be no longer than 15 characters.  They
* must correspond on a one-to-one basis with the file locations in
* the DFILES array.  That is, the first area name in DAREAS must
* be the name that you wish for the first data file set in the
* DFILES array.  You may, of course, have the arrays the same if
* the location of the data file is no longer than 15 characters.
* The locations of the grid files may be differ for each
* installation.  If the pathnames are not correct DFILES (and, possibly,
* DAREAS) may be changed and the program recompiled.


      GFLAG = .FALSE.

c  pick up the state file if no file is in area.par.

        write(LUOUT,90) 
  90    FORMAT(//,' "README.210" documentation file contains ',
     + 'the names of the states',/,
     + 'which have High Precision grids.',/, 
     + ' Please refer to that file before running NADCON',
     + ///)

    	write(LUOUT,91) MXSAREA
  91	format('When prompted, enter the two-letter name for the ',/,
     +  'states or state groups you choose',/,'Enter <CR> when ', 
     +  'finished',/,'MAXIMUM STATES = ',I3)

c 3/94 - read up to maxsdef states first;  then loop to open files
c        looks better
	do j=1,mxsdef
	  write(6,*) 'enter a 2-letter state or <CR> to end'
	  READ(LUIN,95) tstate(j)
  95       FORMAT(A2)
	  if(tstate(j).eq.'  ') then
	    jt = j -1
	    go to 96
	  else
	    jt = j
	  end if
c end of reading in states
	end do

   96   do 140 IDEF = 1,jt
c	  WRITE(LUOUT,'(/)')
	  AFILE = B65
c attach SUN directory locations; assume same for both vixen, venus
c  3/94 - jmb
	  state = tstate(IDEF)
	  AFILE='/ngslib/data/'//state//'hpgn'
c	  AFILE(1:2) = state
c	  AFILE(3:6) = 'hpgn'

* Do not print error messages for non-existing files.

        ITEMP = NAREA + 1
        CALL OPENFL (AFILE, ITEMP, GFLAG, NOGO, DX1, DY1,
     +               XMAX1, XMIN1, YMAX1, YMIN1, NC1, DUM)

        IF (.NOT. NOGO) THEN

* Set of files opened OK and variables read

          NAREA = ITEMP
c         AREAS(NAREA) = DAREAS(IDEF)
          AREAS(NAREA) = state//'hpgn'
          DX(NAREA) = DX1
          DY(NAREA) = DY1
          XMAX(NAREA) = XMAX1
          XMIN(NAREA) = XMIN1
          YMAX(NAREA) = YMAX1
          YMIN(NAREA) = YMIN1
          NC(NAREA) = NC1

c         WRITE (LUOUT,120) NAREA, AREAS(NAREA)
c 120     FORMAT (2X, I2, 2X, A15)
	  write(LUOUT,121) NAREA, state
  121     FORMAT (2X,I2,2X,A2)
        ENDIF

  140 CONTINUE

  999 RETURN
      END