[Image-SIG] .DCX files and dpi information

Chris Barker Chris.Barker at noaa.gov
Mon Jun 2 20:30:54 EDT 2003

Larry Bates wrote:

> i.info returns (1728, 2159) which is pixels of horizontal and vertical
> dots on the page.
> Question: How can I obtain the resolution (e.g. dpi) of the pixels as
> they are encoded in the file?  The faxes can come in in either 100
> or 200 dpi vertical resolution (e.g. fine setting on fax machine) and

Well, it's a kludge, but if you can't get the info directly, it's pretty
obvious that the above example is 200 dpi (1728 / 200. = 8.64), unless
someone is sending a fax from a machine that can handle 17in wide paper.
If the options are really only 100 or 200 dpi, it shojuld be easy to
figure it out for any reasonable image.


Christopher Barker, Ph.D.
NOAA/OR&R/HAZMAT         (206) 526-6959   voice
7600 Sand Point Way NE   (206) 526-6329   fax
Seattle, WA  98115       (206) 526-6317   main reception

Chris.Barker at noaa.gov

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