Kontinuation commented on code in PR #1150:
URL: https://github.com/apache/sedona/pull/1150#discussion_r1433404799
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common/src/main/java/org/apache/sedona/common/raster/MapAlgebra.java:
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@@ -180,6 +174,86 @@ public static GridCoverage2D mapAlgebra(GridCoverage2D
gridCoverage2D, String pi
}
}
+ public static GridCoverage2D mapAlgebra(GridCoverage2D gridCoverage2D,
String pixelType, String script) {
+ return mapAlgebra(gridCoverage2D, pixelType, script, null);
+ }
+
+ private static ColorModel fetchColorModel(ColorModel originalColorModel,
WritableRaster resultRaster) {
+ if (originalColorModel.isCompatibleRaster(resultRaster)) {
+ return originalColorModel;
+ }else {
+ return PlanarImage.createColorModel(resultRaster.getSampleModel());
+ }
+ }
+
+ public static GridCoverage2D mapAlgebra(GridCoverage2D rast0,
GridCoverage2D rast1, String pixelType, String script, Double noDataValue) {
+ if (rast0 == null || rast1 == null || script == null) {
+ return null;
+ }
+ RasterUtils.isRasterSameShape(rast0, rast1);
+
+ RenderedImage renderedImageRast0 = rast0.getRenderedImage();
+ int rasterDataType = pixelType != null ?
RasterUtils.getDataTypeCode(pixelType) :
renderedImageRast0.getSampleModel().getDataType();
+ int width = renderedImageRast0.getWidth();
+ int height = renderedImageRast0.getHeight();
+ // ImageUtils.createConstantImage is slow, manually constructing a
buffered image proved to be faster.
+ // It also eliminates the data-copying overhead when converting raster
data types after running jiffle script.
+ WritableRaster resultRaster =
RasterFactory.createBandedRaster(DataBuffer.TYPE_DOUBLE, width, height, 1,
null);
+
+ ColorModel cmRast0 =
fetchColorModel(renderedImageRast0.getColorModel(), resultRaster);
+ RenderedImage renderedImageRast1 = rast1.getRenderedImage();
+ ColorModel cmRast1 =
fetchColorModel(renderedImageRast1.getColorModel(), resultRaster);
+
+ // todo temp, figure out if needed
+ if (!cmRast0.equals(cmRast1)) {
+ throw new IllegalArgumentException("Color Model did not match.
Provide rasters that has the same properties.");
+ }
+
+ WritableRenderedImage resultImage = new BufferedImage(cmRast0,
resultRaster, false, null);
+ try {
+ String prevScript = previousScript.get();
+ JiffleDirectRuntime prevRuntime = previousRuntime.get();
+ JiffleDirectRuntime runtime;
+ if (prevRuntime != null && script.equals(prevScript)) {
+ // Reuse the runtime to avoid recompiling the script
+ runtime = prevRuntime;
+ runtime.setSourceImage("rast0", renderedImageRast0);
+ runtime.setSourceImage("rast1", renderedImageRast1);
+ runtime.setDestinationImage("out", resultImage);
+ runtime.setDefaultBounds();
+ } else {
+ JiffleBuilder builder = new JiffleBuilder();
+ runtime = builder.script(script)
+ .source("rast0", renderedImageRast0)
+ .source("rast1", renderedImageRast1)
+ .dest("out", resultImage)
+ .getRuntime();
+ previousScript.set(script);
+ previousRuntime.set(runtime);
+ }
+
+ // TODO is it worth to deduplicate code from 236-246 in this
function
+ // TODO and code from 160-171?
+
+ runtime.evaluateAll(null);
+
+ // If pixelType does not match with the data type of the result
image (should be double since Jiffle only supports
+ // double destination image), we need to convert the resultImage
to the specified pixel type.
+ if (rasterDataType != resultImage.getSampleModel().getDataType()) {
Review Comment:
`convertedRaster.setSamples` casts double values to the data type of the
pixel type. It does not round the values.
PostGIS does [something more
complicated](https://github.com/postgis/postgis/blob/3.3.0/raster/rt_core/rt_util.c#L34-L84):
it clamps the value according to the range of data type. It does not round the
values.
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