Merci Martin,
Much neater code, thanks. What I was doing wrong was to use a
non-reprojected geometry parameter when asking for both reprojection and
downsampling. I thought I tried that, but I used the wrong method to
reproject the envelope; the semantics of the resample operation does not per
se suggest which envelope is expected, original or transformed, when a
transformation is also requested.
I'm posting some working and commented stress-test code, so it's online in
case anyone has the same doubts :)
Thanks again,
Ferdinando
-----
// get input file - a 512x512 EPSG:26711 (NAD27 / 11)
final GeoTiffReader reader = new GeoTiffReader(new File(
"d:\\A\\utm.tif"));
final GridCoverage2D source = (GridCoverage2D) reader.read(null);
source.show();
// range corresponding to original size
GeneralGridRange range512 = new GeneralGridRange(new int[]
{0, 0}, new int[] {512, 512});
Envelope2D quarterEnvelope = source.getEnvelope2D();
quarterEnvelope.height /= 2;
quarterEnvelope.width /= 2;
// original envelope (NAD27)
ReferencedEnvelope nad27Envelope =
new ReferencedEnvelope(source.getEnvelope2D(),
source.getCoordinateReferenceSystem());
ReferencedEnvelope nad27QuarterEnvelope =
new ReferencedEnvelope(quarterEnvelope,
source.getCoordinateReferenceSystem());
// half-resolution range
GeneralGridRange range256 = new GeneralGridRange(new int[]
{0, 0}, new int[] {256, 256});
// WSG84-transformed envelope
ReferencedEnvelope wgs84Envelope = null;
ReferencedEnvelope wgs84QuarterEnvelope = null;
try {
wgs84Envelope =
nad27Envelope.transform(DefaultGeographicCRS.WGS84, true, 10);
wgs84QuarterEnvelope =
nad27QuarterEnvelope.transform(DefaultGeographicCRS.WGS84, true, 10);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
// all these geometries work when passed to resample with
the appropriate projection
final GridGeometry2D gridGeometry_512_NAD27 = new
GridGeometry2D(range512, nad27Envelope);
final GridGeometry2D gridGeometry_512_WGS84 = new
GridGeometry2D(range512, wgs84Envelope);
final GridGeometry2D gridGeometry_256_NAD27 = new
GridGeometry2D(range256, nad27Envelope);
final GridGeometry2D gridGeometry_256_WGS84 = new
GridGeometry2D(range256, wgs84Envelope);
final GridGeometry2D gridGeometry_512_NAD27_Q = new
GridGeometry2D(range512, nad27QuarterEnvelope);
final GridGeometry2D gridGeometry_512_WGS84_Q = new
GridGeometry2D(range512, wgs84QuarterEnvelope);
final GridGeometry2D gridGeometry_256_NAD27_Q = new
GridGeometry2D(range256, nad27QuarterEnvelope);
final GridGeometry2D gridGeometry_256_WGS84_Q = new
GridGeometry2D(range256, wgs84QuarterEnvelope);
// choose one of the above; comment out the reprojection if
using a NAD27 geometry
DefaultProcessor processor = new DefaultProcessor(null);
ParameterValueGroup resampleParams =
processor.getOperation("Resample").getParameters();
resampleParams.parameter("Source").setValue(source);
resampleParams.parameter("CoordinateReferenceSystem").setValue(DefaultGeogra
phicCRS.WGS84);
resampleParams.parameter("GridGeometry").setValue(gridGeometry_512_WGS84_Q);
// resample
final GridCoverage2D destination =
(GridCoverage2D)processor.doOperation(resampleParams);
destination.show("transformed");
-----Original Message-----
From: Martin Desruisseaux [mailto:[EMAIL PROTECTED]
Sent: Thursday, March 27, 2008 5:39 AM
To: Ferdinando Villa
Cc: [email protected]
Subject: Re: [Geotools-gt2-users] Problem in coverage projection +
resampling
Typo:
Martin Desruisseaux a écrit :
> You would not suggest instantiate Resample() and invoke its
doOperation(...)
> method. I suggest to invoke processor.doOperation(resampleParams) instead.
Was supposed to be:
I would not suggest to instantiate Resample() and invoke its
doOperation(...)
method. I suggest to invoke processor.doOperation(resampleParams) instead.
-------------------------------------------------------------------------
Check out the new SourceForge.net Marketplace.
It's the best place to buy or sell services for
just about anything Open Source.
http://ad.doubleclick.net/clk;164216239;13503038;w?http://sf.net/marketplace
_______________________________________________
Geotools-gt2-users mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
