2D Grid Files
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.
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.
