(Redirected to user list where it should live)
Here is some working code (
https://gist.github.com/ianturton/e54c41169ef32f48b1ac9b93c580e165) - but I
suspect it could be much more efficient.
Ian
On 9 January 2018 at 11:27, Ian Turton <ijtur...@gmail.com> wrote:
> There may be a better way than this but I would start by creating the new
> raster
>
> WritableRaster writableRaster = RasterFactory.
> createBandedRaster(java.awt.image.DataBuffer.TYPE_DOUBLE, width,
> height, 1, null);
> GridCoverageFactory factory = CoverageFactoryFinder.
> getGridCoverageFactory(null);
> GridCoverage2D gc = factory.create("ResPop", writableRaster, bounds);
>
> copying the old one in to it and then clipping my raster to the envelope
> of the polygon
>
> public GridCoverage2D clip(GridCoverage2D coverage, ReferencedEnvelope
> envelope) {
> CoverageProcessor processor = CoverageProcessor.getInstance();
>
> // An example of manually creating the operation and parameters we want
> final ParameterValueGroup param = processor.getOperation("
> CoverageCrop").getParameters();
> param.parameter("Source").setValue(coverage);
> param.parameter("Envelope").setValue(envelope);
>
> return (GridCoverage2D) processor.doOperation(param);
>
> }
>
> and then step through the remaining pixels - checking if the centre(?) was
> in the polygon and changing them as required
>
> GridEnvelope gridRange2D = grid.getGridGeometry().getGridRange();
> for(int i=gridRange2D.getLow(0);i<gridRange2D.getHigh(0);i++) {
> for(int j=gridRange2D.getLow(1);j<gridRange2D.getHigh(1);j++) {
> Point2D p = grid.gridToWorld(new GridCoordinate2D(i,j));
> if(poly.contains(p)){
> int[] dest = new int[1];
> grid.evaluate(new GridCoordinates2D(i, j), dest );
> System.out.println(i+","+j+"="+dest[0]);
> writableRaster.setDataElements(c.x, c.y, data);
> }
> }
> }
>
> I haven't actually tested any of this but it looks plausible
>
> Ian
>
> On 9 January 2018 at 09:41, Jan Boonen <jan.boo...@geodan.nl> wrote:
>
>> Hi list,
>>
>> For a complex GIS editing application I want to use GeoTools to replace
>> values in a coverage. The cells, whose values need to be replaced, must be
>> selected using an intersection with a JTS Geometry. All editing may be done
>> on in-memory coverages, only the end result will be written to a file.
>>
>> I have read through the tutorials and JavaDoc, but thus far I haven't
>> been able to figure out how to do an intersection on a coverage and how to
>> replace the value of individual cells. Would anybody be so kind to give me
>> some hints?
>>
>> Thanks in advance!
>>
>> Cheers,
>>
>> Jan
>>
>> ------------------------------------------------------------
>> ------------------
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>>
>>
>
>
> --
> Ian Turton
>
--
Ian Turton
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