|   | Name | Type | Identifier | Description | Constraints | 
| Input | Variable | Grid list (input) | VARIABLE | - | - | 
 | Level Heights (*) | Grid list (optional input) | X_GRIDS | - | - | 
 | Minimum Height (*) | Grid (optional input) | X_GRIDS_CHECK | if set, only values with level heights above DEM will be used | - | 
 | Surface | Grid (input) | SURFACE | - | - | 
| Output | Interpolation | Grid (output) | RESULT | - | - | 
| Options | Get Heights from ... | Choice | X_SOURCE | - | Available Choices: [0] table [1] grid list Default: 1 | 
 | Level Heights | Static table | X_TABLE | - | 1 Fields: - 1. [8 byte floating point number] Height
  | 
 | Horizontal Interpolation Method | Choice | H_METHOD | - | Available Choices: [0] Nearest Neighbor [1] Bilinear Interpolation [2] Inverse Distance Interpolation [3] Bicubic Spline Interpolation [4] B-Spline Interpolation Default: 4 | 
 | Vertical Interpolation Method | Choice | V_METHOD | - | Available Choices: [0] linear [1] spline [2] polynomial trend [3] polynomial trend (coefficient interpolation) Default: 0 | 
 | Sorted Levels | Boolean | LINEAR_SORTED | - | Default: 0 | 
 | Pre-analyze | Boolean | SPLINE_ALL | - | Default: 0 | 
 | Polynomial Order | Integer | TREND_ORDER | - | Minimum: 1 Default: 3 | 
| (*) optional |