1r.mapcalc.simple(1)         GRASS GIS User's Manual        r.mapcalc.simple(1)
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NAME

6       r.mapcalc.simple  - Calculates a new raster map from a simple r.mapcalc
7       expression.
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KEYWORDS

10       raster, algebra, simple
11

SYNOPSIS

13       r.mapcalc.simple
14       r.mapcalc.simple --help
15       r.mapcalc.simple   [-sqc]   expression=string    [a=name]      [b=name]
16       [c=name]    [d=name]   [e=name]   [f=name]  output=name  [seed=integer]
17       [--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui]
18
19   Flags:
20       -s
21           Generate random seed (result is non-deterministic)
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23       -q
24           Quote the map names
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26       -c
27           Case sensitive variable names
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29       --overwrite
30           Allow output files to overwrite existing files
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32       --help
33           Print usage summary
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35       --verbose
36           Verbose module output
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38       --quiet
39           Quiet module output
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41       --ui
42           Force launching GUI dialog
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44   Parameters:
45       expression=string [required]
46           Formula (e.g. A-B or A*C+B)
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48       a=name
49           Name of input A raster map
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51       b=name
52           Name of input B raster map
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54       c=name
55           Name of input C raster map
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57       d=name
58           Name of input D raster map
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60       e=name
61           Name of input E raster map
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63       f=name
64           Name of input F raster map
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66       output=name [required]
67           Name for output raster map
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69       seed=integer
70           Seed for rand() function
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DESCRIPTION

73       r.mapcalc.simple provides a wrapper to r.mapcalc.  Up to 6 maps can  be
74       combined using simple expressions.
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76       The general syntax for the expression follows r.mapcalc expression for‐
77       mat, for example, A + B or exp(A + B) are valid.  The variables  A,  B,
78       ...,  F  represent raster maps which are provided as options a, b, ...,
79       f.
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81       The result name, i.e. the output raster  map,  is  provided  using  the
82       option output and, unlike r.mapcalc it is not part of the expression.
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84       This  module is meant for convenience (for users and programmers) while
85       the r.mapcalc module is a better choice for  more  complex  expressions
86       and advanced usage.
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NOTES

89       Differences to r.mapcalc module:
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91           ·   The  input  raster map names and the output map raster name are
92               separate from the expression (formula) which uses generic vari‐
93               able names (A, B, C, ...).
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95           ·   The output raster name is not included in the expression.
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97           ·   The expression is expected to be a single short one liner with‐
98               out the function eval().
99       Differences to r.mapcalc.simple module in GRASS GIS 5 and 6:
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101           ·   The primary purpose is not being a GUI front end to  r.mapcalc,
102               but  a  wrapper  which  allows  easy  building of interfaces to
103               r.mapcalc (including GUIs).
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105           ·   Whitespace (most notably spaces) are allowed (in the  same  way
106               as for r.mapcalc).
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108           ·   The  variable  names are case-insensitive to allow the original
109               uppercase as well as lowercase as in option names  (unless  the
110               -c flag is used).
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112           ·   Option names for each map are just one letter (not amap, etc.).
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114           ·   Output  option  name  is  output as for other modules (not out‐
115               file).
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117           ·   Raster map names can be optionally quoted (the -q flag).
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119           ·   There is no expert mode (which was just running r.mapcalc).
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121           ·   The expression option is first, so it is possible to  omit  its
122               name in the command line (just like with r.mapcalc).
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124           ·   Overwriting  of  outputs  is done in the same way as with other
125               modules, so there is no flag to not overwrite outputs.
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EXAMPLES

128   Basic examples
129       r.mapcalc.simple expression="0" output=zeros
130       r.mapcalc.simple expression="1" output=ones
131       r.mapcalc.simple expression="2" output=twos
132       r.mapcalc.simple expression="A + B + C" a=zeros b=ones c=twos output=result1
133       r.mapcalc.simple expression="(A * B) / 2 + 3 * C" a=zeros b=ones c=twos output=result2
134       Figure: r.mapcalc.simple graphical user interface
135
136   Example expressions
137       Addition:
138       A + B
139       No spaces around operators are not  recommended  for  readability,  but
140       allowed in the expression:
141       A+B
142       More complex expression with a function:
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144       exp(A+C)+(B-2)*7
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SEE ALSO

147        r.mapcalc, r3.mapcalc, t.rast.mapcalc, g.region
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AUTHORS

150       Vaclav Petras, NCSU GeoForAll Lab
151       Michael Barton, Arizona State University (updated to GRASS 5.7)
152       R. Brunzema (original 5.0 Bash version)
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SOURCE CODE

155       Available at: r.mapcalc.simple source code (history)
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157       Main  index  | Raster index | Topics index | Keywords index | Graphical
158       index | Full index
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160       © 2003-2020 GRASS Development Team, GRASS GIS 7.8.5 Reference Manual
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164GRASS 7.8.5                                                r.mapcalc.simple(1)