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

[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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