pamshadedrelief(1)

1Pamshadedrelief User Manual(0)                  Pamshadedrelief User Manual(0)
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NAME

6       pamshadedrelief - generate shaded relief image from an elevation map
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SYNOPSIS

10       pamshadedrelief
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12       [-gamma g]
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DESCRIPTION

17       This program is part of Netpbm(1).
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19       pamshadedrelief creates a shaded relief image from an elevation map.  A
20       shaded relief image is a visual image of terrain, showing  the  terrain
21       as  if  illuminated by oblique light and viewed from above, so that the
22       brightess of each spot depends upon its slope.  A common example  of  a
23       shaded relief image is a relief map of the Earth, which shows mountains
24       and valleys.
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26       The image pamshadedrelief creates is as if illumated by a light  source
27       from the left.
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29       The output image is a PAM with tuple type GRAYSCALE.
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31       The  program  pamcrater is a good thing to use to demonstrate the func‐
32       tion of pamshadedrelief.  It generates a  terrain  map  of  a  cratered
33       landscape.
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35           $ pamcrater | pamshadedrelief | pamx
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OPTIONS

41       All options can be abbreviated to their shortest unique prefix.
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45       -gamma factor
46              The  specified  factor  is used to gamma adjust the image in the
47              same manner as performed by pnmgamma.  The default value is 1.0,
48              which  results in a medium contrast image.  Values larger than 1
49              lighten the image and reduce contrast, while values less than  1
50              darken the image, increasing contrast.
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52              Note  that  this  is  separate from the gamma correction that is
53              part of the definition of the PAM GRAYSCALE format.   The  image
54              pamshadedrelief  generates  is  a  genuine,  gamma-corrected PAM
55              GRAYSCALE image in any case.  This  option  simply  changes  the
56              contrast  and  may compensate for a display device that does not
57              correctly render PAM GRAYSCALE images.
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DESIGN NOTES

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

78       pgmcrater, from which this is derived, was written by John Walker:
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80       John Walker
81       Autodesk SA
82       Avenue des Champs-Montants 14b
83       CH-2074 MARIN
84       Suisse/Schweiz/Svizzera/Svizra/Switzerland
85           Usenet:kelvin@Autodesk.com
86           Fax:038/33 88 15
87           Voice:038/33 76 33
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89       Permission  to  use, copy, modify, and distribute this software and its
90       documentation for any purpose and without fee is hereby granted,  with‐
91       out  any conditions or restrictions.  This software is provided "as is"
92       without express or implied warranty.
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HISTORY

97       pgmcrater was split into pamshadedrelief and pamcrater in Netpbm  10.68
98       (September  2014).  See the history section of the pamcrater manual for
99       details.
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DOCUMENT SOURCE

102       This manual page was generated by the Netpbm tool 'makeman'  from  HTML
103       source.  The master documentation is at
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105              http://netpbm.sourceforge.net/doc/pamshadedrelief.html
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107netpbm documentation             26 July 2014   Pamshadedrelief User Manual(0)