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2003.12.26 02:25 "problems with custom TIFF", by Pushkar Pradhan
I'm working on a TIFF created by ERDAS IMAGINE 8.6, a remote sensing/GIS
software.
The file info as given by tiffinfo (it warns about a few custom tags that it
can't read, these are above 32000):
Image Width: 421 Image Length: 295
Resolution: 1, 1 (unitless)
Bits/Sample: 16
Sample Format: unsigned integer
Compression Scheme: None
Photometric Interpretation: min-is-black
Extra Samples: 2<unspecified, unspecified>
Orientation: row 0 top, col 0 lhs
Samples/Pixel: 3
Rows/Strip: 9
Planar Configuration: single image plane
Software: IMAGINE TIFF Support
I read in the 3 bands using TIFFReadEncodedStrip and write out to a new file
(after converting RGB to LHS in IEEE FP format). This is info given by
tiffinfo of output file:
Image Width: 421 Image Length: 295
Bits/Sample: 32
Sample Format: IEEE floating point
Compression Scheme: None
Photometric Interpretation: min-is-black
Samples/Pixel: 3
Rows/Strip: 9
Planar Configuration: single image plane
However, the software is unable to open this file. I suspect this has got
something to do with the Extra Samples: 2<unspecified, unspecified> thing? I
found out that this tells whether there is alpha information in the file or
not. But can somebody explain to me how to read it? The man page is
confusing. Also once I get it what should I do with it when writing out the
output file?
Here's my code for more information:
size = TIFFReadEncodedStrip(tif, strip, bufRGB, (tsize_t)-1);
Rgb2Lhs(bufRGB, bufRGB+size, bufRGB+(size*2), tags.dType, tags.config,
bufLHS, bufLHS+size, bufLHS+(size*2),
tags.imageLength, tags.rowsPerStrip);
size = TIFFWriteEncodedStrip(wtif, strip, bufLHS, size*sizeof(float));
Thanks,
Pushkar Pradhan