Re: [Geotools-gt2-users] Any suggestions about geotiff?

[Jody G. <jod...@gm...>]

Have you read the javadocs?
- http://java.sun.com/j2se/1.3/docs/api/java/awt/image/Raster.html#getSample(int,
int, int)

You need to call the correct getSample method to match the data type
stored in the raster.

For more information (beyond the javadocs) please review the JAI Manual:
- http://java.sun.com/products/java-media/jai/forDevelopers/jai1_0_1guide-unc/

Jody

2009/4/15 xx <xia...@16...>:
> I tried this:
> GeoTiffReader reader = new GeoTiffReader(new
> FileInputStream(strfile).getChannel());
> GridCoverage2D c = (GridCoverage2D) reader.read(null);
> RenderedImage img = c.getRenderedImage();
> RandomIter iter = RandomIterFactory.create(img, null);
> int s = iter.getSample(x, y, 0);
>
> but the result is different from the bufferedimage.getRGB(x,y), it is much
> smaller than this.
> it looks like getSample don't return the value of a image.
> what's the return value of a getSample operation?
>
>
> 在2009-04-15，"Jody Garnett" <jod...@gm...> 写道：
>>We use PlanarImage as I recall; the idea with these things is *not*
>>GetRGB(x,y) / SetRGB(x,y) but to set up a chain of JAI operations that
>>accomplishes something. You can get the raster and sample out some RGB
>>values (but that will "pull" pixels through the chain).
>>
>>The chapter here
>>http://docs.codehaus.org/display/GEOTDOC/08+Grid+Coverage has some
>>examples. But you may just want to read through the JAI reference
>>material?
>>
>>Jody
>>PS. If you can please keep reply's to the user list
>>
>>
>>2009/4/14 xx <xia...@16...>:
>>> Jody, thanks very much. but I looked through the user guide and didn't
>>> find
>>> information about how to access the pixel of a image, like
>>> BufferedImage.GetRGB(x,y)  and SetRGB(x,y)in java. I can only get a
>>> GridCoverage from a geotiff file. How can I get some objects as
>>> bufferedimage from the gridCoverage , or any other way to access the
>>> pixel ?
>>>
>>>
>>> 在2009-04-14，"Jody Garnett" <jod...@gm...> 写道：
>>>>Check out the user guide; geotiff is handled just like any of the grid
>>>>coverage formats (ie raster formats).
>>>>I recommend making use of the Reader and Writer directly rather than
>>>>relying on the FormatFinder; but the user guide should get you
>>>>started.
>>>>
>>>>Jody
>>>>
>>>>2009/4/14 xx <xia...@16...>:
>>>>> Hello,
>>>>>      Everybody, I am a fresh to geotools. And I intend to read and
>>>>> write
>>>>> geotiff image with geotools . But I don't know how to start my work. Is
>>>>> there any guide or tutorials for this?
>>>>> Thanks
>>>>>
>>>>>
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>
>
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