You can save the histogram to various image formats. Here is an example from a set of Landsat bands 1-5, and 7. It took about 1 second to histogram all 6 bands.
http://dl.dropbox.com/u/7437464/histogramtest.png
____________________
C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social Change
Arizona State University
voice: 480-965-6262 (SHESC), 480-727-9746 (CSDC)
fax: 480-965-7671 (SHESC), 480-727-0709 (CSDC)
www: http://www.public.asu.edu/~cmbarton, http://csdc.asu.edu
On Sep 22, 2011, at 7:28 PM, <grass-dev-request@lists.osgeo.org> wrote:
Date: Wed, 21 Sep 2011 22:25:05 -0700
From: Michael Barton <Michael.Barton@asu.edu>
Subject: [GRASS-dev] New histogramming tool for GRASS 7
To: GRASS developers grass-developers <grass-dev@lists.osgeo.org>
Message-ID: <4940725D-199D-49EC-BB3E-703AE35FA7E0@asu.edu>
Content-Type: text/plain; charset="us-ascii"Something that I've thought about for quite awhile but only now managed to get around to doing. I have added a new histogramming tool to GRASS 7, based on PyPlot like the profiling tool. It will histogram a single raster map or all the maps in an imagery group. It gives user control over colors and line styles, axes, legends, fonts, and grid.
It is available from the analysis toolbar button on the display canvas as "Create histogram with PyPlot" for now. I've left in the old tool that displays d.hist in a window. It should be especially useful for image analysis.
Give it a try and let me know if you hit any bugs.