pamshadedrelief(1) - phpMan

Pamshadedrelief User Manual(0)                                     Pamshadedrelief User Manual(0)



NAME
       pamshadedrelief - generate shaded relief image from an elevation map


SYNOPSIS
       pamshadedrelief

       [-gamma g]



DESCRIPTION
       This program is part of Netpbm(1).

       pamshadedrelief  creates  a  shaded  relief  image from an elevation map.  A shaded relief
       image is a visual image of terrain, showing the terrain as if illuminated by oblique light
       and  viewed from above, so that the brightess of each spot depends upon its slope.  A com-
       mon example of a shaded relief image is a relief map of the Earth, which  shows  mountains
       and valleys.

       The image pamshadedrelief creates is as if illumated by a light source from the left.

       The output image is a PAM with tuple type GRAYSCALE.

       The  program  pamcrater  is  a  good thing to use to demonstrate the function of pamshade-
       drelief.  It generates a terrain map of a cratered landscape.

           $ pamcrater | pamshadedrelief | pamx




OPTIONS
       All options can be abbreviated to their shortest unique prefix.



       -gamma factor
              The specified factor is used to gamma adjust the image in the same manner  as  per-
              formed  by  pnmgamma.  The default value is 1.0, which results in a medium contrast
              image.  Values larger than 1 lighten the image and reduce  contrast,  while  values
              less than 1 darken the image, increasing contrast.

              Note that this is separate from the gamma correction that is part of the definition
              of the PAM GRAYSCALE format.  The image pamshadedrelief  generates  is  a  genuine,
              gamma-corrected  PAM  GRAYSCALE  image in any case.  This option simply changes the
              contrast and may compensate for a display device that does not correctly render PAM
              GRAYSCALE images.




DESIGN NOTES
       The-gamma  option  isn't  really necessary since you can achieve the same effect by piping
       the output from pamshadedrelief through pnmgamma.  However,  pamshadedrelief  performs  an
       internal  gamma  map  anyway  in the process of rendering the elevation array into the PAM
       GRAYSCALE format, so there's no  additional  overhead  in  allowing  an  additional  gamma
       adjustment.



SEE ALSO
       ppmrelief(1) pnmgamma(1), pnmsmooth(1) pamcrater(1) pam(1),



AUTHOR
       pgmcrater, from which this is derived, was written by John Walker:

       John Walker
       Autodesk SA
       Avenue des Champs-Montants 14b
       CH-2074 MARIN
       Suisse/Schweiz/Svizzera/Svizra/Switzerland
           Usenet:kelvin AT Autodesk.com
           Fax:038/33 88 15
           Voice:038/33 76 33

       Permission  to  use,  copy, modify, and distribute this software and its documentation for
       any purpose and without fee is hereby granted, without  any  conditions  or  restrictions.
       This software is provided "as is" without express or implied warranty.



HISTORY
       pgmcrater  was  split into pamshadedrelief and pamcrater in Netpbm 10.68 (September 2014).
       See the history section of the pamcrater manual for details.

DOCUMENT SOURCE
       This manual page was generated by the Netpbm tool 'makeman' from HTML source.  The  master
       documentation is at

              http://netpbm.sourceforge.net/doc/pamshadedrelief.html

netpbm documentation                       26 July 2014            Pamshadedrelief User Manual(0)

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