Fill NoData by Spline Interpolation
Overview
Spline interpolation fills NoData cells by fitting a smooth surface through surrounding valid values. It is suitable for continuous rasters where smoothness is more important than preserving sharp local extremes.
Use Cases
- Fill NoData holes in continuous raster data with smooth transitions.
- Prepare spatially continuous raster input for later zonal statistics, threshold extraction, or map production.
- Repair gaps before visualization or downstream analysis.
Parameters
| Parameter | Description | Notes |
|---|---|---|
| Input raster file | Raster file whose NoData cells need spline interpolation | Required |
| Output raster file | Output raster file after spline interpolation | Required |
Steps
- Start the tool: Open Geoprocessing Toolbox → Spatial Analysis Tools > Raster Synthesis > Fill NoData, then start the Fill NoData by Spline Interpolation tool pane.
- Prepare input: Select the Input raster file and confirm that the data is complete and readable.
- Set core parameters: Confirm that the NoData areas to be filled are appropriate for spline interpolation.
- Set output: Specify the Output raster file and confirm that the output path, format, and naming rules meet downstream requirements.
- Run and inspect the result: Click Run, then check whether filled cells, value range, and spatial position meet expectations.
Notes
- Spline interpolation can smooth local extremes, so it may not be suitable when sharp breaks must be preserved.
- Use a projected coordinate system for distance-sensitive interpolation when possible.
- Sparse valid cells, uneven distribution, or outliers can reduce the reliability of the filled surface.