Re: [Geotools-gt2-users] Getting world coordinates by Mouseclick, Mousebehaviour on StyledMapPane

[Martin S. <sp...@mo...>]

I fixed it. No bug in GT! Was a fault of myself!!

When I specify new colors for an existing GridCoverage, I create a new 
BufferedImage with a corresponding ColorModel and then a new 
GridCoverage of the BufferedImage.
And there was a (copy/paste-)bug in the creation of the BufferedImage:
I created it with
         BufferedImage bufIm  = new BufferedImage(
             raster.getHeight(),
             raster.getHeight(),
             ...
         )
instead of
         BufferedImage bufIm  = new BufferedImage(
             raster.getWidth(),
             raster.getHeight(),
             ...
         )

So my displayed raster was a little bit deformed compared to my original 
raster (from which I determined the raster value to the mouse position)!

Sorry for my unnecessary question...

Martin Schmitz


Martin Desruisseaux schrieb:
> Martin Schmitz a écrit :
> 
>> In the vertical direction everything is exactly correct. The problem 
>> is the horizontal.
>>
>> As I found out just a minute ago, the reason seems not to be the 
>> method GeoMouseEvent.getMapCoordinate(.) because if I move the cursor 
>> in the lower left corner, it returns the correct lat/lon position of 
>> my raster! So the problem must be GridCoverage.evaluate(Point2D,.).
>>
>> Is there a bug in the transformation from the lat/lon to raster 
>> coordinates? Rounding problems?
> 
> 
> Not as far as I know. It seems to work correctly on my own software (but 
> I may be wrong - more tests would be better). There is no separated 
> processing for the horizontal and the vertical axis. Most 
> transformations are handled by java.awt.geom.AffineTransform, which 
> handle both axis simultaneously. An error may occurs while setting up 
> the AffineTransform however. I suggest to try the following:
> 
>  MathTransform tr = 
> gridCoverage.getGridGeometry().getGridToCoordinateSystem();
>  System.out.println(tr);
> 
> Make sure that the affine transform coefficients are the expected one.
> 
> The AffineTransform can be setup by GridCoverage2D at construction time 
> from the image size and an user-supplied Envelope. Make sure that the 
> envelope is correct. If the envelope is correct but GridCoverage2D setup 
> an incorrect AffineTransform, please let me know.
> 
>     Martin.
>