ecearth3/sources/nemo-3.6/NEMO/OPA_SRC/OBS/maxdist.h90

   !!----------------------------------------------------------------------
   !! NEMO/OPA 3.3 , NEMO Consortium (2010)
   !! $Id: maxdist.h90 2287 2010-10-18 07:53:52Z smasson $
   !! Software governed by the CeCILL licence (NEMOGCM/NEMO_CeCILL.txt)
   !!----------------------------------------------------------------------

   REAL FUNCTION maxdist( pxv, pyv )
      !!----------------------------------------------------------------------
      !!                    ***  FUNCTION maxdist ***
      !!
      !! ** Purpose : Compute the maximum distance between any points within
      !!              a cell
      !!
      !! ** Method  : Call to grt_cir_dis
      !!
      !! ** Action  : 
      !!
      !! History :
      !!        !  2006-08  (K. Mogensen)
      !!        !  2006-10  (A. Weaver) Cleanup
      !!----------------------------------------------------------------------

      !! * Arguments
      REAL(KIND=wp), DIMENSION(4), INTENT(IN) :: &
          & pxv, &                 ! (lon, lat) of the surrounding cell
          & pyv    

      !! * Local declarations
      REAL(KIND=wp), DIMENSION(4) :: &
          &  zxv, &
          &  zyv, &
          &  za,  &
          &  zb,  &
          &  zc
      REAL(KIND=wp) :: zdist
      
      INTEGER :: ji
      INTEGER :: jj
      
      !-----------------------------------------------------------------------
      ! Convert data to radians
      !-----------------------------------------------------------------------
      DO ji = 1, 4
         zxv(ji) = pxv(ji) * rad
         zyv(ji) = pyv(ji) * rad
      END DO

      !-----------------------------------------------------------------------
      ! Prepare input to grt_cir_dis
      !-----------------------------------------------------------------------
      DO ji = 1, 4
         za(ji) = SIN( zyv(ji) )
         zb(ji) = COS( zyv(ji) ) * COS( zxv(ji) )
         zc(ji) = COS( zyv(ji) ) * SIN( zxv(ji) )
      END DO
      
      !-----------------------------------------------------------------------
      ! Get max distance between any points in the area
      !-----------------------------------------------------------------------
      maxdist = 0.0
      DO jj = 1, 4
         DO ji = jj+1, 4
            zdist = grt_cir_dis( za(jj), za(ji), zb(jj), &
               &                 zb(ji), zc(jj), zc(ji))
            IF ( zdist > maxdist ) THEN
               maxdist = zdist
            ENDIF
         END DO
      END DO
      
      !-----------------------------------------------------------------------
      ! Convert to degrees.
      !-----------------------------------------------------------------------
      maxdist = maxdist / rad

   END FUNCTION maxdist