NAME

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

KEYWORDS

       raster, algebra, simple

SYNOPSIS

       r.mapcalc.simple
       r.mapcalc.simple --help
       r.mapcalc.simple   [-sqc]   expression=string    [a=name]    [b=name]    [c=name]    [d=name]    [e=name]
       [f=name]  output=name  [seed=integer]   [--overwrite]  [--help]  [--verbose]  [--quiet]  [--ui]

   Flags:
       -s
           Generate random seed (result is non-deterministic)

       -q
           Quote the map names

       -c
           Case sensitive variable names

       --overwrite
           Allow output files to overwrite existing files

       --help
           Print usage summary

       --verbose
           Verbose module output

       --quiet
           Quiet module output

       --ui
           Force launching GUI dialog

   Parameters:
       expression=string [required]
           Formula (e.g. A-B or A*C+B)

       a=name
           Name of input A raster map

       b=name
           Name of input B raster map

       c=name
           Name of input C raster map

       d=name
           Name of input D raster map

       e=name
           Name of input E raster map

       f=name
           Name of input F raster map

       output=name [required]
           Name for output raster map

       seed=integer
           Seed for rand() function

DESCRIPTION

       r.mapcalc.simple provides a wrapper to r.mapcalc.  Up to 6 maps can be combined using simple expressions.

       The general syntax for the expression follows r.mapcalc expression format, for example, A + B or exp(A  +
       B)  are valid.  The variables A, B, ..., F represent raster maps which are provided as options a, b, ...,
       f.

       The result name, i.e. the output raster map, is provided using the option output and, unlike r.mapcalc it
       is not part of the expression.

       This  module  is meant for convenience (for users and programmers) while the r.mapcalc module is a better
       choice for more complex expressions and advanced usage.

NOTES

       Differences to r.mapcalc module:

           •   The input raster map names and the output map  raster  name  are  separate  from  the  expression
               (formula) which uses generic variable names (A, B, C, ...).

           •   The output raster name is not included in the expression.

           •   The expression is expected to be a single short one liner without the function eval().
       Differences to r.mapcalc.simple module in GRASS GIS 5 and 6:

           •   The  primary  purpose  is not being a GUI front end to r.mapcalc, but a wrapper which allows easy
               building of interfaces to r.mapcalc (including GUIs).

           •   Whitespace (most notably spaces) are allowed (in the same way as for r.mapcalc).

           •   The variable names are case-insensitive to allow the original uppercase as well as  lowercase  as
               in option names (unless the -c flag is used).

           •   Option names for each map are just one letter (not amap, etc.).

           •   Output option name is output as for other modules (not outfile).

           •   Raster map names can be optionally quoted (the -q flag).

           •   There is no expert mode (which was just running r.mapcalc).

           •   The expression option is first, so it is possible to omit its name in the command line (just like
               with r.mapcalc).

           •   Overwriting of outputs is done in the same way as with other modules, so there is no flag to  not
               overwrite outputs.

EXAMPLES

   Basic examples
       r.mapcalc.simple expression="0" output=zeros
       r.mapcalc.simple expression="1" output=ones
       r.mapcalc.simple expression="2" output=twos
       r.mapcalc.simple expression="A + B + C" a=zeros b=ones c=twos output=result1
       r.mapcalc.simple expression="(A * B) / 2 + 3 * C" a=zeros b=ones c=twos output=result2
       Figure: r.mapcalc.simple graphical user interface

   Example expressions
       Addition:
       A + B
       No spaces around operators are not recommended for readability, but allowed in the expression:
       A+B
       More complex expression with a function:

       exp(A+C)+(B-2)*7

SEE ALSO

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

AUTHORS

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

SOURCE CODE

       Available at: r.mapcalc.simple source code (history)

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       © 2003-2019 GRASS Development Team, GRASS GIS 7.8.2 Reference Manual