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
11 [-gamma g]
13
17 This program is part of Netpbm(1).
18 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.
25 The image pamshadedrelief creates is as if illumated by a light source
27 from the left.
28 The output image is a PAM with tuple type GRAYSCALE.
30 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.
34 $ pamcrater | pamshadedrelief | pamx
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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:
45 -gamma factor
49 -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.
56 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.
63
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.
74
78 ppmrelief(1) pnmgamma(1), pnmsmooth(1) pamcrater(1) pam(1),
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83 pgmcrater, from which this is derived, was written by John Walker:
84 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
93 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.
98
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.
105
107 This manual page was generated by the Netpbm tool 'makeman' from HTML
108 source. The master documentation is at
109 http://netpbm.sourceforge.net/doc/pamshadedrelief.html
111netpbm documentation 26 July 2014 Pamshadedrelief User Manual(0)