1Pamshadedrelief User Manual(0) Pamshadedrelief User Manual(0)
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6 pamshadedrelief - generate shaded relief image from an elevation map
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10 pamshadedrelief
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12 [-gamma g]
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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
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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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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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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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73 ppmrelief(1) pnmgamma(1), pnmsmooth(1) pamcrater(1) pam(1),
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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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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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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)