public static GridCoverage2D interpolate()

in common/src/main/java/org/apache/sedona/common/raster/RasterEditors.java [619:713]
82 lines of code
19 McCabe index (conditional complexity)

  public static GridCoverage2D interpolate(
      GridCoverage2D inputRaster,
      Double power,
      String mode,
      Double numPointsOrRadius,
      Double maxRadiusOrMinPoints,
      Integer band)
      throws IllegalArgumentException {
    if (!mode.equalsIgnoreCase("variable") && !mode.equalsIgnoreCase("fixed")) {
      throw new IllegalArgumentException(
          "Invalid 'mode': '" + mode + "'. Expected one of: 'Variable', 'Fixed'.");
    }

    Raster rasterData = inputRaster.getRenderedImage().getData();
    WritableRaster raster =
        rasterData.createCompatibleWritableRaster(
            RasterAccessors.getWidth(inputRaster), RasterAccessors.getHeight(inputRaster));
    int width = raster.getWidth();
    int height = raster.getHeight();
    int numBands = raster.getNumBands();
    GridSampleDimension[] gridSampleDimensions = inputRaster.getSampleDimensions();

    if (band != null && (band < 1 || band > numBands)) {
      throw new IllegalArgumentException("Band index out of range.");
    }

    // Interpolation for each band
    for (int bandIndex = 0; bandIndex < numBands; bandIndex++) {
      if (band == null || bandIndex == band - 1) {
        // Generate STRtree
        STRtree strtree = RasterInterpolate.generateSTRtree(inputRaster, bandIndex);
        Double noDataValue = RasterUtils.getNoDataValue(inputRaster.getSampleDimension(bandIndex));
        int countNoDataValues = 0;

        // Skip band if STRtree is empty or has all valid data pixels
        if (strtree.isEmpty() || strtree.size() == width * height) {
          continue;
        }

        if (mode.equalsIgnoreCase("variable") && strtree.size() < numPointsOrRadius) {
          throw new IllegalArgumentException(
              "Parameter 'numPoints' is larger than no. of valid pixels in band "
                  + bandIndex
                  + ". Please choose an appropriate value");
        }

        // Perform interpolation
        for (int y = 0; y < height; y++) {
          for (int x = 0; x < width; x++) {
            double value = rasterData.getSampleDouble(x, y, bandIndex);
            if (Double.isNaN(value) || value == noDataValue) {
              countNoDataValues++;
              double interpolatedValue =
                  RasterInterpolate.interpolateIDW(
                      x,
                      y,
                      strtree,
                      width,
                      height,
                      power,
                      mode,
                      numPointsOrRadius,
                      maxRadiusOrMinPoints);
              interpolatedValue =
                  (Double.isNaN(interpolatedValue)) ? noDataValue : interpolatedValue;
              if (interpolatedValue != noDataValue) {
                countNoDataValues--;
              }
              raster.setSample(x, y, bandIndex, interpolatedValue);
            } else {
              raster.setSample(x, y, bandIndex, value);
            }
          }
        }

        // If all noDataValues are interpolated, update band metadata (remove nodatavalue)
        if (countNoDataValues == 0) {
          gridSampleDimensions[bandIndex] =
              RasterUtils.removeNoDataValue(inputRaster.getSampleDimension(bandIndex));
        }
      } else {
        raster.setSamples(
            0,
            0,
            raster.getWidth(),
            raster.getHeight(),
            band,
            rasterData.getSamples(
                0, 0, raster.getWidth(), raster.getHeight(), band, (double[]) null));
      }
    }

    return RasterUtils.clone(
        raster, inputRaster.getGridGeometry(), gridSampleDimensions, inputRaster, null, true);
  }