Hi Mike,
I've just tried your code (slightly modified). The problem is a bug in
VectorToRasterProcess.
I'm not sure it's had much use with point features - other folk have
used it for polygons and lines so you may be forging a new path :) I
haven't worked out what the problem is but there is definitely a
problem. However, I'm afraid I won't be able to get to it for some
time.
Meanwhile, if you don't mind getting your hands dirty with some JAI
code you could rasterize your points as in the snippet below. If you
try it, let me know how it goes.
Michael
GridCoverageFactory gcf =
CoverageFactoryFinder.getGridCoverageFactory(null);
WritableRaster raster =
RasterFactory.createBandedRaster(DataBuffer.TYPE_FLOAT, numCols,
numRows, 1, new java.awt.Point(0, 0));
GridCoverage2D cov = gcf.create("mycov", raster, new
ReferencedEnvelope(minx, maxx, miny, maxy, crs));
GridGeometry2D gg = cov.getGridGeometry();
SimpleFeatureIterator iter = collection.features();
try {
while (iter.hasNext()) {
SimpleFeature feature = iter.next();
Geometry p = (Geometry) feature.getDefaultGeometry();
Float value = (Float) feature.getAttribute("value");
Coordinate pcoord = p.getCoordinate();
DirectPosition pos = new DirectPosition2D(pcoord.x, pcoord.y);
GridCoordinates2D gc = gg.worldToGrid(pos);
raster.setSample(gc.x, gc.y, 0, value);
}
} finally {
iter.close();
}
Michael
On 2 April 2011 12:17, Mike O'Toole <[email protected]> wrote:
> Thank You Michael.
>
> That solved my problem perfectly. I'm now having an issue with the evaluate
> returning 0.0 every time. The following is a simplified version of my code. I
> have a latitude, longitude, and value for points that I'm creating a feature
> collection with. I then use the VectorToRasterProcess to create my
> GridCoverage. I've read through all the documentation and can't seem to
> figure out what I'm missing. Again pointing me in the right direction is
> greatly appreciated.
>
> -Mike
>
> // Setup CRS
> Hints hints = new Hints( Hints.CRS, DefaultEngineeringCRS.CARTESIAN_2D );
> GeometryFactory geometryFactory = JTSFactoryFinder.getGeometryFactory( hints
> );
>
> SimpleFeatureType TYPE =
> DataUtilities.createType("location","geom:Point,value:Float");
>
> SimpleFeatureCollection collection =
> FeatureCollections.newCollection("ExampleSetFeatureCollection");
>
> // Loop and add features
> Coordinate coord1 = new Coordinate( currentLat, currentLon);
> Point point1 = geometryFactory.createPoint( coord1 );
> SimpleFeature feature = SimpleFeatureBuilder.build( TYPE, new Object[]{
> point1, currentDoubleValue.floatValue() }, null );
> collection.add( feature );
>
> // Setup for process
> ProgressListener progress = new ProgressWindow(null);
> Dimension gridDim = new Dimension(1000,1000);
>
> GridCoverage2D gridCoverage = VectorToRasterProcess.process(
> collection,
> "value",
> gridDim,
> collection.getBounds(),
> "ExampleSetGridCoverage",
> progress);
>
> // Create point with known location from my raw data.
> DirectPosition point = new
> DirectPosition2D(DefaultEngineeringCRS.CARTESIAN_2D, 38.969614330552,
> -121.512359247084);
> float[] value = (float[]) gridCoverage.evaluate(point);
>
> // This shows the point to be 0.0 no matter the location I give it.
> System.out.println("Known Point: Lat:38.969614330552 Lon:-121.512359247084
> value:" + value[0]);
>
>
> On Mar 29, 2011, at 11:12 PM, Michael Bedward wrote:
>
>> Hi Mike,
>>
>> It's just Java's typing being a bit painful. A DirectPosition2D
>> object is a Point2D object with geospatial extras.
>>
>> What I usually do use DirectPosition references instead which avoids
>> the ambiguity...
>>
>> DirectPosition pos = new DirectPosition2D(myCRS, x, y);
>> dest = cov.evaluate(pos, dest);
>>
>> The only hassle with this is that you can no longer say pos.x and
>> pos.y. Instead you have to say pos.getOrdinate(0) and
>> pos.getOrdinate(1) which is clunky.
>>
>> The other option of course is to explicitly cast...
>>
>> DirectPosition2D pos = new DirectPosition2D(myCRS, x, y);
>> dest = cov.evaluate( (DirectPosition2D)pos, dest);
>>
>> Your mission is to decide which of these is the least worst :)
>>
>> Hope that helps,
>>
>> Michael
>>
>>
>> On 30 March 2011 15:38, Mike O'Toole <[email protected]> wrote:
>>> Hello all,
>>> I'm brand new to GeoTools. I'm trying to use the evaluate() method on my
>>> GridCoverge2D object. However I get a reference to evaluate is ambiguous
>>> error.
>>> Error:
>>> reference to evaluate is ambiguous, both method
>>> evaluate(org.opengis.geometry.DirectPosition,double[]) in
>>> org.geotools.coverage.AbstractCoverage and method
>>> evaluate(java.awt.geom.Point2D,double[]) in
>>> org.geotools.coverage.grid.GridCoverage2D match
>>>
>>> Here is the code snippet:
>>> DirectPosition2D nextPoint = new DirectPosition2D(sphericalMercator, x, y);
>>>
>>> double[] dest = gridCoverage.evaluate(nextPoint, dest);
>>>
>>> Any help pointing me in the right direction is greatly appreciated and let
>>> me know if more information is needed.
>>> Thank You,
>>> Mike
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