2D Grid Files

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Two-dimensional grids are stored in 2D grid files. The grids can be either cell-centered or mesh-centered. If the grid is mesh-centered, a set of material IDs may be included in the file. The 2D grid file format is shown in Figure 1, and a sample file in Figure 2.

GRID2D /* File type */
TYPE i /* Type of grid. Mesh or Cell centered. */
IJ ±idir ±jdir /* Card for defining rows, columns. */
DIM nx ny /* # of cell boundaries in each direction. */
x1 /* X coord. of cell boundaries. */
x2
.
.
xnx
y1 /* Y coord. of cell boundaries. */
y2
.
.
yny
DELEV el /* Default elevation for grid. */

Figure 1. 2D Grid File Format.

GRID2D
ID 5758
TYPE 1
DELEV 0.000000000000000e+00
IJ -y +x
DIM 4 4
0.000000000000000e+00
3.333333333333334e+01
6.666666666666667e+01
1.000000000000000e+02
0.000000000000000e+00
3.333333333333334e+01
6.666666666666667e+01
1.000000000000000e+02

Figure 2. Sample 2D Grid File.

2D Grid Files Card Types

The card types used in the 2D grid file format are as follows:

Card Type GRID2D
Description File type identifier. Must be on first line of file. No fields.
Required YES


Card Type TYPE
Description Defines the type of grid as either cell- or mesh-centered.
Required YES
Format TYPE i
Sample TYPE 0
Field Variable Value Description
1 i 0,1 The type code:
  • i = 0 for mesh-centered
  • i = 1 for cell-centered


Card Type IJ
Description Defines the orientation of the i,j indices.
Required YES
Format IJ ±idir ±jdir
Sample IJ +x -y
Field Variable Value Description
1 ±idir ±x,±y The direction corresponding to an increasing i index.
2 ±jdir ±x,±y The direction corresponding to an increasing j index.


Card Type DIM
Description Defines the dimensions of the grid.
Required YES
Format
DIM nx ny
x1
x2
.
.
xnx
y1
y2
.
.
yny
Sample
DIM 4 6
0.0
1.0
2.0
4.0
10.0
12.0
14.0
16.0
18.0
20.0
Field Variable Value Description
1 nx + The number of cell boundaries in the x direction.
2 ny + The number of cell boundaries in the y direction.
3 to (nx+2) x1-xnx ± The coordinates of the x boundaries.
(nx+3) to (nx+ny+2) y1-yny ± The coordinates of the y boundaries.


Card Type DELEV
Description Defines a default elevation for the grid.
Required NO
Format DELEV el
Sample DELEV 100.0
Field Variable Value Description
1 el ± The default elevation.


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