Add Raster constructor for creating a new Raster from a matrix of values. Add pixelSize and blockSize methods

Author: jericks

doc/api/raster.rst

@@ -55,6 +55,9 @@ Methods
 
     A Raster is a spatial data set represented by a grid of cells organized in one or more bands.
 
+    Usually, Rasters are read from a Format, but you can create a new Raster from an array or array of numeric values
+    and a geom.Bounds.
+
 Properties
 ----------
 
@@ -99,6 +102,16 @@ Properties
     `Object` with min and max arrays with min and max values for each band
     Get the minimum and maximum values for each band.
 
+.. attribute:: Raster.blockSize
+
+    `Array` with width and height of a pixel
+    Get the block size
+
+.. attribute:: Raster.pixelSize
+
+    `Array` with width and height of a pixel
+    Get the pixel size
+
 Methods
 -------
 

src/main/java/org/geoscript/js/raster/Raster.java

@@ -5,14 +5,14 @@
 import org.geoscript.js.geom.Geometry;
 import org.geoscript.js.geom.Point;
 import org.geoscript.js.proj.Projection;
-import org.geotools.coverage.grid.GridCoordinates2D;
-import org.geotools.coverage.grid.GridCoverage2D;
-import org.geotools.coverage.grid.GridEnvelope2D;
-import org.geotools.coverage.grid.GridGeometry2D;
+import org.geotools.coverage.Category;
+import org.geotools.coverage.GridSampleDimension;
+import org.geotools.coverage.grid.*;
 import org.geotools.coverage.processing.CoverageProcessor;
 import org.geotools.geometry.DirectPosition2D;
 import org.geotools.geometry.jts.ReferencedEnvelope;
 import org.geotools.process.raster.RangeLookupProcess;
+import org.geotools.util.NumberRange;
 import org.jaitools.numeric.Range;
 import org.mozilla.javascript.*;
 import org.mozilla.javascript.annotations.JSConstructor;
@@ -25,7 +25,12 @@
 import org.opengis.referencing.crs.CoordinateReferenceSystem;
 import org.opengis.referencing.operation.TransformException;
 
+import javax.media.jai.RasterFactory;
+import java.awt.*;
+import java.awt.image.DataBuffer;
+import java.awt.image.WritableRaster;
 import java.util.*;
+import java.util.List;
 
 public class Raster extends GeoObject implements Wrapper {
 
@@ -218,6 +223,25 @@ public Object getMaxValue(int band) {
         return maxValue;
     }
 
+    @JSGetter
+    public NativeArray getBlockSize() {
+        int[] size = this.coverage.getOptimalDataBlockSizes();
+        return (NativeArray) javaToJS(Arrays.asList(
+                size[0],
+                size[1]
+        ), this.getParentScope());
+    }
+
+    @JSGetter
+    public NativeArray getPixelSize() {
+        Bounds bounds = this.getBounds();
+        NativeArray size = this.getSize();
+        return (NativeArray) javaToJS(Arrays.asList(
+                ((double) bounds.getWidth()) / ((int)size.get(0)),
+                ((double) bounds.getHeight()) / ((int)size.get(1))
+        ), this.getParentScope());
+    }
+
     private int getInt(Object obj) {
         if (obj instanceof Number) {
             return ((Number)obj).intValue();
@@ -238,10 +262,44 @@ public Object unwrap() {
 
     @JSConstructor
     public static Object constructor(Context cx, Object[] args, Function ctorObj, boolean inNewExpr) {
+        NativeArray data = (NativeArray) args[0];
+        Bounds bounds = (Bounds) args[1];
+
+        double min = Double.MAX_VALUE;
+        double max = Double.MIN_VALUE;
+        float[][] matrix = new float[(int) data.getLength()][ (int) (data.getLength() > 0 ? ((NativeArray) data.get(0)).getLength() : 0)];
+        for(int i = 0; i<data.getLength(); i++) {
+            NativeArray datum = (NativeArray) data.get(i);
+            for(int j = 0; j<datum.getLength(); j++) {
+                float value = ((Number)datum.get(j)).floatValue();
+                if (!Float.isNaN(value) && value < min) {
+                    min = value;
+                }
+                if (!Float.isNaN(value) && value > max) {
+                    max = value;
+                }
+                matrix[i][j] = value;
+            }
+        }
+
+        int width = matrix[0].length;
+        int height = matrix.length;
+
+        WritableRaster writableRaster = RasterFactory.createBandedRaster(DataBuffer.TYPE_FLOAT, width, height, 1, null);
+        for(int i = 0; i<width; i++) {
+            for(int j = 0; j<height; j++) {
+                writableRaster.setSample(i, j, 0, matrix[j][i]);
+            }
+        }
+
+        GridCoverageFactory gridCoverageFactory = new GridCoverageFactory();
+        Category category = new Category("Raster", Color.BLACK, NumberRange.create(min, max));
+        GridSampleDimension gridSampleDimension = new GridSampleDimension("Raster", new Category[]{category}, null);
+        GridCoverage2D coverage = gridCoverageFactory.create("Raster", writableRaster, bounds.unwrap(), new GridSampleDimension[]{gridSampleDimension});
         if (inNewExpr) {
-            return new Raster(null);
+            return new Raster(coverage);
         } else {
-            return new Raster(ctorObj.getParentScope(), null);
+            return new Raster(ctorObj.getParentScope(), coverage);
         }
     }
 

src/test/resources/org/geoscript/js/tests/geoscript/raster/test_raster.js

@@ -5,6 +5,17 @@ var raster = require("geoscript/raster");
 var geom = require('geoscript/geom');
 var proj = require('geoscript/proj');
 
+exports["test: create a raster from data"] = function() {
+    var ras = new raster.Raster([
+     [1,1,1,1,1],
+     [1,2,2,2,1],
+     [1,2,3,2,1]
+    ], new geom.Bounds([0,0,10,10]))
+    assert.ok(ras instanceof raster.Raster, "instance should be Raster");
+    assert.strictEqual(1, ras.getMinValue(), "Min value should be 1");
+    assert.strictEqual(3, ras.getMaxValue(), "Max value should be 3");
+};
+
 exports["test: read a raster"] = function() {
     var format = new raster.Format({source: admin.raster.source});
     var tif = format.read({});
@@ -136,6 +147,22 @@ exports["test: get min and max values for a raster band"] = function() {
     assert.strictEqual(255, tif.getMaxValue(0));
 };
 
+exports["test: get block size"] = function() {
+    var format = new raster.Format({source: admin.raster.source});
+    var tif = format.read({});
+    var blockSize = tif.blockSize;
+    assert.strictEqual(900, blockSize[0], "Block Size Width should be 900");
+    assert.strictEqual(9, blockSize[1], "Block Size Height should be 9 ");
+};
+
+exports["test: get pixel size"] = function() {
+    var format = new raster.Format({source: admin.raster.source});
+    var tif = format.read({});
+    var pixelSize = tif.pixelSize;
+    assert.strictEqual(0.4, pixelSize[0], "Pixel Size Width should be 0.4");
+    assert.strictEqual(0.4, pixelSize[1], "Pixel Size Height should be 0.4");
+};
+
 exports["test: get extrema for all raster bands"] = function() {
     var format = new raster.Format({source: admin.raster.source});
     var tif = format.read({});