bad pixel values after a reprojection

[fred poubelle]

Hello
I get an error when reprojecting an image : the values of the pixels in the result image are one unit lesser than the corresponding pixels in the original image.
Have I made a mistake somewhere in the provided code ? Is it a bug due to GeoTools or to JAI or... ?
Below is the code I have used, you will find the image file in attachment.
Thanks for your help.
Fred






import java.awt.Point;
import java.awt.geom.Point2D;
import java.awt.image.RenderedImage;
import java.awt.image.renderable.

ParameterBlock;

import javax.media.jai.Interpolation;
import javax.media.jai.JAI;
import javax.media.jai.RenderedOp;

import org.geotools.coverage.grid.GridCoverage2D;
import org.geotools.coverage.grid.GridCoverageFactory;
import org.geotools.coverage.processing.Operations;
import org.geotools.geometry.Envelope2D;
import org.geotools.referencing.CRS;
import org.opengis.geometry.Envelope;



/**
 * Reprojects a PGM file.
 * The values of all the result file's pixels all are one unit lesser than the original file's corresponding pixel.
 *
 * Usage : java ReprojectionProblem
 */
public class ReprojectionProblem {
    public static void main (String[] args) {

        try {

            // loading the input file
            RenderedOp rop = JAI.create("fileload", "in.pgm");

            // getting a gridcoverage whithin the input file
            GridCoverageFactory fac = new GridCoverageFactory();       
            GridCoverage2D  gc = fac.create("NO NAME",rop.getAsBufferedImage() , new Envelope2D(CRS.decode("EPSG:4326"),-20,-20,40,40));

            // displaying the value at coordinates point (0,0) BEFORE reprojection
            int[] array = new int[1];
            Point2D pt = new Point(0,0);
            gc.evaluate(pt, array);
            System.out.println("BEFORE: " + array[0]);

            // getting the target Envelope
            Envelope env = new Envelope2D(CRS.decode("EPSG:4326"),-40,-40,80,80);

            // reprojecting
            GridCoverage2D gc2 = (GridCoverage2D)Operations.DEFAULT.resample(gc,env,Interpolation.getInstance(Interpolation.INTERP_BILINEAR));

            // displaying the value at coordinates point (0,0) AFTER reprojection
            array = new int[1];
            pt = new Point(0,0);
            gc2.evaluate(pt, array);
            System.out.println("AFTER: " + array[0]);

            // getting the result image
            RenderedImage res = gc2.getRenderedImage();

            // saving the result image
            ParameterBlock pb = new ParameterBlock();
            pb.addSource(res);
            pb.add("out.pgm");
            pb.add("pnm");
            JAI.create("filestore", pb);


        } catch (Exception e) {
            e.printStackTrace();
        }




    }
}

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[Simone Giannecchini]

Ciao Fred,
please, read below...
-------------------------------------------------------
Ing. Simone Giannecchini
GeoSolutions S.A.S.
Owner - Software Engineer
Via Carignoni 51
55041  Camaiore (LU)
Italy

phone: [phone]
fax:      [phone]
mob:    [phone]


http://www.geo-solutions.it
http://geo-solutions.blogspot.com/
http://simboss.blogspot.com/
http://www.linkedin.com/in/simonegiannecchini

-------------------------------------------------------



On Wed, Jul 8, 2009 at 7:26 PM, fred p<[hidden email]> wrote:
> Hello
> I get an error when reprojecting an image : the values of the pixels in the
> result image are one unit lesser than the corresponding pixels in the
> original image.
> Have I made a mistake somewhere in the provided code ? Is it a bug due to
> GeoTools or to JAI or... ?

I would not use the filestore/fileload operation from JAI, I would
rather use the ImageRead/ImageWrite bridge between JAI and ImageIO.
However, PNM support in imageio is buggy, data are not written out
correctly. I did fixe some of the problems in the past but I am not
sure the fixes were applied to the source code.  I might commit those
fixes to imageio-ext, but unless someone steps up with funding, that
is unlikely to happen anytime soon.
If you feel brave, I might pass them over to you.

Simone.

> Below is the code I have used, you will find the image file in attachment.
> Thanks for your help.
> Fred
>
>
>
>
>
>
> import java.awt.Point;
> import java.awt.geom.Point2D;
> import java.awt.image.RenderedImage;
> import java.awt.image.renderable.
> ParameterBlock;
>
> import javax.media.jai.Interpolation;
> import javax.media.jai.JAI;
> import javax.media.jai.RenderedOp;
>
> import org.geotools.coverage.grid.GridCoverage2D;
> import org.geotools.coverage.grid.GridCoverageFactory;
> import org.geotools.coverage.processing.Operations;
> import org.geotools.geometry.Envelope2D;
> import org.geotools.referencing.CRS;
> import org.opengis.geometry.Envelope;
>
>
>
> /**
>  * Reprojects a PGM file.
>  * The values of all the result file's pixels all are one unit lesser than
> the original file's corresponding pixel.
>  *
>  * Usage : java ReprojectionProblem
>  */
> public class ReprojectionProblem {
>     public static void main (String[] args) {
>
>         try {
>
>             // loading the input file
>             RenderedOp rop = JAI.create("fileload", "in.pgm");
>
>             // getting a gridcoverage whithin the input file
>             GridCoverageFactory fac = new GridCoverageFactory();
>             GridCoverage2D  gc = fac.create("NO
> NAME",rop.getAsBufferedImage() , new
> Envelope2D(CRS.decode("EPSG:4326"),-20,-20,40,40));
>
>             // displaying the value at coordinates point (0,0) BEFORE
> reprojection
>             int[] array = new int[1];
>             Point2D pt = new Point(0,0);
>             gc.evaluate(pt, array);
>             System.out.println("BEFORE: " + array[0]);
>
>             // getting the target Envelope
>             Envelope env = new
> Envelope2D(CRS.decode("EPSG:4326"),-40,-40,80,80);
>
>             // reprojecting
>             GridCoverage2D gc2 =
> (GridCoverage2D)Operations.DEFAULT.resample(gc,env,Interpolation.getInstance(Interpolation.INTERP_BILINEAR));
>
>             // displaying the value at coordinates point (0,0) AFTER
> reprojection
>             array = new int[1];
>             pt = new Point(0,0);
>             gc2.evaluate(pt, array);
>             System.out.println("AFTER: " + array[0]);
>
>             // getting the result image
>             RenderedImage res = gc2.getRenderedImage();
>
>             // saving the result image
>             ParameterBlock pb = new ParameterBlock();
>             pb.addSource(res);
>             pb.add("out.pgm");
>             pb.add("pnm");
>             JAI.create("filestore", pb);
>
>
>         } catch (Exception e) {
>             e.printStackTrace();
>         }
>
>
>
>
>     }
> }
> ------------------------------------------------------------------------------
> Enter the BlackBerry Developer Challenge
> This is your chance to win up to $100,000 in prizes! For a limited time,
> vendors submitting new applications to BlackBerry App World(TM) will have
> the opportunity to enter the BlackBerry Developer Challenge. See full prize
> details at: http://p.sf.net/sfu/Challenge
> _______________________________________________
> Geotools-gt2-users mailing list
> [hidden email]
> https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
>
>

------------------------------------------------------------------------------
Enter the BlackBerry Developer Challenge  
This is your chance to win up to $100,000 in prizes! For a limited time,
vendors submitting new applications to BlackBerry App World(TM) will have
the opportunity to enter the BlackBerry Developer Challenge. See full prize  
details at: http://p.sf.net/sfu/Challenge
_______________________________________________
Geotools-gt2-users mailing list
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[fred poubelle]

Hello,

Thanks Simone for your answer. I unfortunately do not have enough time for the moment to accept your proposition about the fixes to imageio-ext. Discovering the GeoTools is a long job ! Sorry...

However, the problem do not seem to be due to the fileload operation from JAI because the printed values of an arbitrary point just before the GeoTools' resample operation are right. They are wrong just after it. That is why I suspect a bug in GeoTools or in the JAI components it might use. Have you got any idea ?

Thanks for your help.

Fred

2009/7/8 Simone Giannecchini <[hidden email]>

Ciao Fred,
please, read below...
-------------------------------------------------------
Ing. Simone Giannecchini
GeoSolutions S.A.S.
Owner - Software Engineer
Via Carignoni 51
55041  Camaiore (LU)
Italy

phone: [phone]
fax:      [phone]
mob:    [phone]


http://www.geo-solutions.it
http://geo-solutions.blogspot.com/
http://simboss.blogspot.com/
http://www.linkedin.com/in/simonegiannecchini

-------------------------------------------------------

On Wed, Jul 8, 2009 at 7:26 PM, fred p<[hidden email]> wrote:
> Hello
> I get an error when reprojecting an image : the values of the pixels in the
> result image are one unit lesser than the corresponding pixels in the
> original image.
> Have I made a mistake somewhere in the provided code ? Is it a bug due to
> GeoTools or to JAI or... ?

I would not use the filestore/fileload operation from JAI, I would
rather use the ImageRead/ImageWrite bridge between JAI and ImageIO.
However, PNM support in imageio is buggy, data are not written out
correctly. I did fixe some of the problems in the past but I am not
sure the fixes were applied to the source code.  I might commit those
fixes to imageio-ext, but unless someone steps up with funding, that
is unlikely to happen anytime soon.
If you feel brave, I might pass them over to you.

Simone.

> Below is the code I have used, you will find the image file in attachment.
> Thanks for your help.
> Fred
>
>
>
>
>
>
> import java.awt.Point;
> import java.awt.geom.Point2D;
> import java.awt.image.RenderedImage;
> import java.awt.image.renderable.
> ParameterBlock;
>
> import javax.media.jai.Interpolation;
> import javax.media.jai.JAI;
> import javax.media.jai.RenderedOp;
>
> import org.geotools.coverage.grid.GridCoverage2D;
> import org.geotools.coverage.grid.GridCoverageFactory;
> import org.geotools.coverage.processing.Operations;
> import org.geotools.geometry.Envelope2D;
> import org.geotools.referencing.CRS;
> import org.opengis.geometry.Envelope;
>
>
>
> /**
>  * Reprojects a PGM file.
>  * The values of all the result file's pixels all are one unit lesser than
> the original file's corresponding pixel.
>  *
>  * Usage : java ReprojectionProblem
>  */
> public class ReprojectionProblem {
>     public static void main (String[] args) {
>
>         try {
>
>             // loading the input file
>             RenderedOp rop = JAI.create("fileload", "in.pgm");
>
>             // getting a gridcoverage whithin the input file
>             GridCoverageFactory fac = new GridCoverageFactory();
>             GridCoverage2D  gc = fac.create("NO
> NAME",rop.getAsBufferedImage() , new
> Envelope2D(CRS.decode("EPSG:4326"),-20,-20,40,40));
>
>             // displaying the value at coordinates point (0,0) BEFORE
> reprojection
>             int[] array = new int[1];
>             Point2D pt = new Point(0,0);
>             gc.evaluate(pt, array);
>             System.out.println("BEFORE: " + array[0]);
>
>             // getting the target Envelope
>             Envelope env = new
> Envelope2D(CRS.decode("EPSG:4326"),-40,-40,80,80);
>
>             // reprojecting
>             GridCoverage2D gc2 =
> (GridCoverage2D)Operations.DEFAULT.resample(gc,env,Interpolation.getInstance(Interpolation.INTERP_BILINEAR));
>
>             // displaying the value at coordinates point (0,0) AFTER
> reprojection
>             array = new int[1];
>             pt = new Point(0,0);
>             gc2.evaluate(pt, array);
>             System.out.println("AFTER: " + array[0]);
>
>             // getting the result image
>             RenderedImage res = gc2.getRenderedImage();
>
>             // saving the result image
>             ParameterBlock pb = new ParameterBlock();
>             pb.addSource(res);
>             pb.add("out.pgm");
>             pb.add("pnm");
>             JAI.create("filestore", pb);
>
>
>         } catch (Exception e) {
>             e.printStackTrace();
>         }
>
>
>
>
>     }
> }

> ------------------------------------------------------------------------------
> Enter the BlackBerry Developer Challenge
> This is your chance to win up to $100,000 in prizes! For a limited time,
> vendors submitting new applications to BlackBerry App World(TM) will have
> the opportunity to enter the BlackBerry Developer Challenge. See full prize
> details at: http://p.sf.net/sfu/Challenge
> _______________________________________________
> Geotools-gt2-users mailing list
> [hidden email]
> https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
>
>

------------------------------------------------------------------------------
Enter the BlackBerry Developer Challenge  
This is your chance to win up to $100,000 in prizes! For a limited time,
vendors submitting new applications to BlackBerry App World(TM) will have
the opportunity to enter the BlackBerry Developer Challenge. See full prize  
details at: http://p.sf.net/sfu/Challenge
_______________________________________________
Geotools-gt2-users mailing list
[hidden email]
https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users