ExtractBorderFloat Subroutine

private subroutine ExtractBorderFloat(grid, border, cardinal)

Extracts only the cells on the external border. Other cells are assigned nodata. Border cell is the one that has at least a nodata value in the neighbouring 8 cells.

Arguments

Type IntentOptional Attributes Name
type(grid_real), intent(in) :: grid
type(grid_real) :: border
logical, intent(in), optional :: cardinal

Variables

Type Visibility Attributes Name Initial
integer, public :: col
logical, public :: foundNodata
logical, public :: fourCells

true if to consider only four cells in cardinal directions
integer, public :: i
integer, public :: j
integer, public :: row

Source Code

SUBROUTINE ExtractBorderFloat &
!
(grid, border, cardinal) 

IMPLICIT NONE

!Arguments with intent in:
TYPE (grid_real), INTENT(IN) :: grid
LOGICAL, INTENT(IN), OPTIONAL :: cardinal

!Arguments with intent in:
TYPE (grid_real) :: border

!Local declaration:
INTEGER :: i,j
LOGICAL :: foundNodata
INTEGER :: row, col
LOGICAL :: fourCells !!true if to consider only four cells in cardinal directions

!---------------------------end of declarations--------------------------------

!Allocate space for grid containing values on the border
CALL NewGrid (border, grid)

IF (PRESENT(cardinal)) THEN
  IF (cardinal) THEN
    fourCells = .TRUE.
  ELSE
    fourCells = .FALSE.
  END IF
ELSE
  fourCells = .FALSE.
END IF

!scan grid
DO i = 1, border % idim
  DO j = 1, border % jdim
    IF (grid % mat (i,j) /= grid % nodata) THEN

          foundNodata = .FALSE.
          
          !check EAST cell
          row = i 
          col = j + 1
          IF ( .NOT. IsOutOfGrid(row,col,border) ) THEN
            IF (grid % mat (row,col) == grid % nodata) THEN
               foundNodata = .TRUE.
               border % mat (i,j) = grid % mat (i,j)
               CYCLE
            END IF
          ELSE
            foundNodata = .TRUE.
            border % mat (i,j) = grid % mat (i,j)
            CYCLE
          END IF
          
          !check SOUTH-EAST cell
          IF ( .NOT. fourCells) THEN
              row = i + 1
              col = j + 1
              IF ( .NOT. IsOutOfGrid(row,col,border) ) THEN
                IF (grid % mat (row,col) == grid % nodata) THEN
                   foundNodata = .TRUE.
                   border % mat (i,j) = grid % mat (i,j)
                   CYCLE
                END IF
              ELSE
                foundNodata = .TRUE.
                border % mat (i,j) = grid % mat (i,j)
                CYCLE
              END IF
          END IF
          !check SOUTH cell
          row = i + 1
          col = j
          IF ( .NOT. IsOutOfGrid(row,col,border) ) THEN
            IF (grid % mat (row,col) == grid % nodata) THEN
               foundNodata = .TRUE.
               border % mat (i,j) = grid % mat (i,j)
               CYCLE
            END IF
          ELSE
            foundNodata = .TRUE.
            border % mat (i,j) = grid % mat (i,j)
            CYCLE
          END IF
          
          !check SOUTH-WEST cell
          IF (.NOT. fourCells) THEN
              row = i + 1
              col = j - 1
              IF ( .NOT. IsOutOfGrid(row,col,border) ) THEN
                IF (grid % mat (row,col) == grid % nodata) THEN
                   foundNodata = .TRUE.
                   border % mat (i,j) = grid % mat (i,j)
                   CYCLE
                END IF
              ELSE
                foundNodata = .TRUE.
                border % mat (i,j) = grid % mat (i,j)
                CYCLE
              END IF
          END IF
          
          !check WEST cell
          row = i 
          col = j - 1
          IF ( .NOT. IsOutOfGrid(row,col,border) ) THEN
            IF (grid % mat (row,col) == grid % nodata) THEN
               foundNodata = .TRUE.
               border % mat (i,j) = grid % mat (i,j)
               CYCLE
            END IF
          ELSE
            foundNodata = .TRUE.
            border % mat (i,j) = grid % mat (i,j)
            CYCLE
          END IF
          
          !check NORTH-EAST cell
          IF (.NOT. fourCells) THEN
              row = i - 1
              col = j - 1
              IF ( .NOT. IsOutOfGrid(row,col,border) ) THEN
                IF (grid % mat (row,col) == grid % nodata) THEN
                   foundNodata = .TRUE.
                   border % mat (i,j) = grid % mat (i,j)
                   CYCLE
                END IF
              ELSE
                foundNodata = .TRUE.
                border % mat (i,j) = grid % mat (i,j)
                CYCLE
              END IF
          END IF
          
          !check NORTH cell
          row = i - 1
          col = j
          IF ( .NOT. IsOutOfGrid(row,col,border) ) THEN
            IF (grid % mat (row,col) == grid % nodata) THEN
               foundNodata = .TRUE.
               border % mat (i,j) = grid % mat (i,j)
               CYCLE
            END IF
          ELSE
            foundNodata = .TRUE.
            border % mat (i,j) = grid % mat (i,j)
            CYCLE
          END IF
          
          !check NORTH-EAST cell
          IF (.NOT. fourCells) THEN
              row = i - 1
              col = j + 1
              IF ( .NOT. IsOutOfGrid(row,col,border) ) THEN
                IF (grid % mat (row,col) == grid % nodata) THEN
                   foundNodata = .TRUE.
                   border % mat (i,j) = grid % mat (i,j)
                   CYCLE
                END IF
              ELSE
                foundNodata = .TRUE.
                border % mat (i,j) = grid % mat (i,j)
                CYCLE
              END IF
          END IF
          
          IF ( .NOT. foundNodata ) THEN
            border % mat (i,j) = border % nodata
          END IF
       
    END IF
  END DO
END DO


END SUBROUTINE ExtractBorderFloat