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 <[email protected]>: > 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" <[email protected]> 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 <[email protected]>: >>> 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" <[email protected]> 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 <[email protected]>: >>>>> 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 >>>>> >>>>> >>>>> ________________________________ >>>>> 网易邮箱，中国第一大电子邮件服务商 >>>>> >>>>> >>>>> ------------------------------------------------------------------------------ >>>>> This SF.net email is sponsored by: >>>>> High Quality Requirements in a Collaborative Environment. >>>>> Download a free trial of Rational Requirements Composer Now! >>>>> http://p.sf.net/sfu/www-ibm-com >>>>> _______________________________________________ >>>>> Geotools-gt2-users mailing list >>>>> [email protected] >>>>> https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users > > > ________________________________ > 网易邮箱，中国第一大电子邮件服务商 > ------------------------------------------------------------------------------ > This SF.net email is sponsored by: > High Quality Requirements in a Collaborative Environment. > Download a free trial of Rational Requirements Composer Now! > http://p.sf.net/sfu/www-ibm-com > _______________________________________________ > Geotools-gt2-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users > > ------------------------------------------------------------------------------ This SF.net email is sponsored by: High Quality Requirements in a Collaborative Environment. Download a free trial of Rational Requirements Composer Now! http://p.sf.net/sfu/www-ibm-com _______________________________________________ Geotools-gt2-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
