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January 2007
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2007.01.17 16:03 "Re: Elevation Data", by Ed Grissom
But.... I don't see any disclaimer on SMin/Smax (Min/Max, sure, but not SMin/SMax) My copy of the spec says: ++++++++++++++++++++++++++++++++++++++++++ SMinSampleValue Tag = 340 (154.H) Type = the field type that best matches the sample data N = SamplesPerPixel This field specifies the minimum sample value. Note that a value should be given for each data sample. That is, if the image has 3 SamplesPerPixel, 3 values must be specified. The default for SMinSampleValue and SMaxSampleValue is the full range of the data type. SMaxSampleValue Tag = 341 (155.H) Type = the field type that best matches the sample data N = SamplesPerPixel This new field specifies the maximum sample value. ++++++++++++++++++++++++++++++++++++++++++ And then the comments say: ++++++++++++++++++++++++++++++++++++++++++ Comments The SampleFormat field allows more general imaging (such as image processing) applications to employ TIFF as a valid file format. SMinSampleValue and SMaxSampleValue become more meaningful when image data is typed. The presence of these fields makes it possible for readers to assume that data samples are bound to the range [SMinSampleValue, SMaxSampleValue] without scanning the image data. ++++++++++++++++++++++++++++++++++++++++++ -- ed grissom ed.grissom@intergraph.com