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

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

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.

Basicexamples
       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.simplegraphicaluserinterfaceExampleexpressions
       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

       raster, algebra, simple

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

       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.

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

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

       Accessed: Friday Apr 04 01:21:12 2025

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       © 2003-2025 GRASS Development Team, GRASS GIS 8.4.1 Reference Manual

GRASS 8.4.1                                                                             r.mapcalc.simple(1grass)

r.mapcalc.simpler.mapcalc.simple--helpr.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