Process Raster Plugin

The gt-process-raster plugin a provides a number of ready to use raster processign chains - and provide a great example of how to work with rasters.

Maven:

<dependency>
   <groupId>org.geotools</groupId>
   <artifactId>gt-process-raster</artifactId>
   <version>${geotools.version}</version>
 </dependency>

Jiffle

The Jiffle process allows to perform map algebra on one or more input rasters. The Jiffle language reference can be found here.

The following test snippet shows how to use Jiffle to multiply two rasters:

public void testMultiply() {
    // build the input rasters
    GridCoverage2D c1 =
            buildCoverage(
                    new float[][] {
                        {1, 0, 0},
                        {0, 1, 0},
                        {0, 0, 1},
                    });
    GridCoverage2D c2 =
            buildCoverage(
                    new float[][] {
                        {2, 2, 2},
                        {2, 2, 2},
                        {2, 2, 2},
                    });

    // invoke the process using the Process interface
    Process jiffle = Processors.createProcess(new NameImpl("ras", "Jiffle"));
    Map<String, Object> inputs = new HashMap<>();
    inputs.put(JiffleProcess.IN_SOURCE_NAME, new String[] {"a", "b"});
    inputs.put(JiffleProcess.IN_COVERAGE, new GridCoverage2D[] {c1, c2});
    inputs.put(JiffleProcess.IN_SCRIPT, "dest = a * b;");
    Map<String, Object> output = jiffle.execute(inputs, null);
    GridCoverage2D result = (GridCoverage2D) output.get(JiffleProcess.OUT_RESULT);

    // test results
    float[][] resultData = data(result);
    float[][] expected =
            new float[][] {
                {2, 0, 0},
                {0, 2, 0},
                {0, 0, 2},
            };
    Assert.assertArrayEquals(expected, resultData);
}