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TIFF and LibTiff Mail List Archive

Thread

2004.03.02 21:17 "[Tiff] Reading caspian.tif", by Simon Granger
2004.03.03 16:40 "Re: [Tiff] Reading caspian.tif", by Andrey Kiselev
2004.03.03 19:52 "Re: [Tiff] Reading caspian.tif", by Bob Friesenhahn
2004.03.03 20:17 "Re: [Tiff] Reading caspian.tif", by Frank Warmerdam
2004.03.03 21:18 "Re: [Tiff] Reading caspian.tif", by Simon Granger
2004.03.03 19:59 "Re: [Tiff] Reading caspian.tif", by Chris Cox

2004.03.03 16:40 "Re: [Tiff] Reading caspian.tif", by Andrey Kiselev

Simon,

On Tue, Mar 02, 2004 at 04:17:19PM -0500, Simon Granger wrote:

I downloaded the TIFF test images at ftp://ftp.remotesensing.org/pub/libtiff/pics-3.6.1.tar.gz, loaded caspian.tif with my own code using libtiff and saw the following problem:

The samples in caspian.tif are double-precision IEEE floating point with no SMINSAMPLEVALUE and SMAXSAMPLEVALUE tags. So when I read the samples, I'm expecting that they'll be in the range [0.0, 1.0]. But they're not: the actual range of all the samples in caspian.tif is [9.0, 946.0].

But why did you expected the values will be in 0.0,1.0 range? If we have floating point data then the whole range can be occupied. For displaying purposes you should find min/max values yourself and scale image properly.

Andrey

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Andrey V. Kiselev

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