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       In  addition  to  the options common to all programs based on libnetpbm
42       (most notably -quiet, see
43        Common Options ⟨index.html#commonoptions⟩  ),  pamshadedrelief  recog‐
44       nizes the following command line option:
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48       -gamma factor
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50       -g factor
51              The  specified  factor  is used to gamma adjust the image in the
52              same manner as performed by pnmgamma.  The default value is 1.0,
53              which  results in a medium contrast image.  Values larger than 1
54              lighten the image and reduce contrast, while values less than  1
55              darken the image, increasing contrast.
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57              Note  that  this  is  separate from the gamma correction that is
58              part of the definition of the PAM GRAYSCALE format.   The  image
59              pamshadedrelief  generates  is  a  genuine,  gamma-corrected PAM
60              GRAYSCALE image in any case.  This  option  simply  changes  the
61              contrast  and  may compensate for a display device that does not
62              correctly render PAM GRAYSCALE images.
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DESIGN NOTES

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

78       ppmrelief(1) pnmgamma(1), pnmsmooth(1) pamcrater(1) pam(1),
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AUTHOR

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

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

107       This manual page was generated by the Netpbm tool 'makeman'  from  HTML
108       source.  The master documentation is at
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110              http://netpbm.sourceforge.net/doc/pamshadedrelief.html
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112netpbm documentation             26 July 2014   Pamshadedrelief User Manual(0)
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