Available grid types:
| Value | Description |
|---|---|
| regularxy | Two-dimensional surface data on a regularly-spaced XY grid. The grid size must be specified on creation (with the initgrid command). |
| regularxyz | Three-dimensional volumetric data on a regularly spaced XYZ grid. The grid size must be specified on creation (with the initgrid command). |
| freexyz | Three-dimensional data not restricted to a regular grid. No grid size specification is necessary. |