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Newsgroups: info.grass.user
Path: zorro.cecer.army.mil!shapiro
From: shapiro@zorro.cecer.army.mil (Michael Shapiro)
Subject: Re: histogram in r.support
Message-ID: <C25DF1.B2t@news.cecer.army.mil>
Sender: news@news.cecer.army.mil (Net.Noise owner)
Organization: US Army Corps of Engineers Construction Engineering Research Labs
References: <9302052030.AA02522@mtqgrass.ESD.ORNL.GOV>
Date: Mon, 8 Feb 1993 20:40:13 GMT
Lines: 36

In <9302052030.AA02522@mtqgrass.ESD.ORNL.GOV> hnw@mtqgrass.ESD.ORNL.GOV (Bill Hargrove) writes:

Hello GrassHoppers:

    When I ask r.support to build a histogram for a raster image, does it
perform a contrast stretch, or does it just record the histogram
distribution of the cells as they currently exist?
                                           Thanks,
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Bill Hargrove
Oak Ridge National Laboratory
Environmental Sciences Division
P.O. Box 2008, M.S. 6038
Oak Ridge, TN 37831-6038
(615) 574-1902
(615) 576-8646 (fax)
hnw@mtqgrass.esd.ornl.gov
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It just builds a file with the histogram in it, not contrast stretch
is done. Mostly you don't need the histogram.
The only program which I think looks at this is i.composite.
If you want to create a contrast-stretched grey scale color map for
an image, use r.colors [map] color=grey.eq
--

Michael Shapiro U.S. Army CERL
Environmental Division