| Code Figure | Meaning |
|---|---|
| 0 |
Data is calculated directly from the source grid with no interpolation (see note 1) |
| 1 |
Bilinear interpolation using the 4 source grid grid-point values surrounding the nominal grid-point |
| 2 |
Bicubic interpolation using the 4 source grid grid-point values surrounding the nominal grid-point |
| 3 |
Using the value from the source grid grid-point which is nearest to the nominal grid-point |
| 4 |
Budget interpolation using the 4 source grid grid-point values surrounding the nominal grid-point (see note 2) |
| 5 |
Spectral interpolation using the 4 source grid grid-point values surrounding the nominal grid-point |
| 6 |
Neighbor-budget interpolation using the 4 source grid grid-point values surrounding the nominal grid-point (see note 3) |
| 7-191 |
Reserved |
| 192-254 |
Reserved for Local Use |
| 255 | Missing |
| Notes: (1) This method assumes that each field really represents box averages/maxima/minima where each box extends halfway to its neighboring grid point in each direction to represent averages/maxima/minima of values from the source grid with no interpolation. (2) Budget interpolation means a low-order interpolation method that quasi-conserves are a averages. It would be appropriate for interpolating budget fields such as precipitation. This method assumes that ithe field really represents box averages/maxima/minima where each box extends halfway to its neighboring grid point in each direction. The method actually averages bilinearly interpolated values in a square array of points distributed within each output grid box. (3) Performs a budget interpolation at the grid point nearest to the nominal grid point. |