.TH r.mapcalc.simple 1grass "" "GRASS 7.8.5" "GRASS GIS User's Manual"
.SH NAME
\fI\fBr.mapcalc.simple\fR\fR  \- Calculates a new raster map from a simple r.mapcalc expression.
.SH KEYWORDS
raster, algebra, simple
.SH SYNOPSIS
\fBr.mapcalc.simple\fR
.br
\fBr.mapcalc.simple \-\-help\fR
.br
\fBr.mapcalc.simple\fR [\-\fBsqc\fR] \fBexpression\fR=\fIstring\fR  [\fBa\fR=\fIname\fR]   [\fBb\fR=\fIname\fR]   [\fBc\fR=\fIname\fR]   [\fBd\fR=\fIname\fR]   [\fBe\fR=\fIname\fR]   [\fBf\fR=\fIname\fR]  \fBoutput\fR=\fIname\fR  [\fBseed\fR=\fIinteger\fR]   [\-\-\fBoverwrite\fR]  [\-\-\fBhelp\fR]  [\-\-\fBverbose\fR]  [\-\-\fBquiet\fR]  [\-\-\fBui\fR]
.SS Flags:
.IP "\fB\-s\fR" 4m
.br
Generate random seed (result is non\-deterministic)
.IP "\fB\-q\fR" 4m
.br
Quote the map names
.IP "\fB\-c\fR" 4m
.br
Case sensitive variable names
.IP "\fB\-\-overwrite\fR" 4m
.br
Allow output files to overwrite existing files
.IP "\fB\-\-help\fR" 4m
.br
Print usage summary
.IP "\fB\-\-verbose\fR" 4m
.br
Verbose module output
.IP "\fB\-\-quiet\fR" 4m
.br
Quiet module output
.IP "\fB\-\-ui\fR" 4m
.br
Force launching GUI dialog
.SS Parameters:
.IP "\fBexpression\fR=\fIstring\fR \fB[required]\fR" 4m
.br
Formula (e.g. A\-B or A*C+B)
.IP "\fBa\fR=\fIname\fR" 4m
.br
Name of input A raster map
.IP "\fBb\fR=\fIname\fR" 4m
.br
Name of input B raster map
.IP "\fBc\fR=\fIname\fR" 4m
.br
Name of input C raster map
.IP "\fBd\fR=\fIname\fR" 4m
.br
Name of input D raster map
.IP "\fBe\fR=\fIname\fR" 4m
.br
Name of input E raster map
.IP "\fBf\fR=\fIname\fR" 4m
.br
Name of input F raster map
.IP "\fBoutput\fR=\fIname\fR \fB[required]\fR" 4m
.br
Name for output raster map
.IP "\fBseed\fR=\fIinteger\fR" 4m
.br
Seed for rand() function
.SH DESCRIPTION
\fIr.mapcalc.simple\fR provides a wrapper to \fIr.mapcalc\fR.
Up to 6 maps can be combined using simple expressions.
.PP
The general syntax for the \fBexpression\fR follows
\fIr.mapcalc\fR 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 \fBa\fR, \fBb\fR, ..., \fBf\fR.
.PP
The result name, i.e. the output raster map, is provided using the
option \fBoutput\fR and, unlike \fIr.mapcalc\fR it is not part
of the expression.
.PP
This module is meant for convenience (for users and programmers) while
the \fIr.mapcalc\fR module is a better choice for more complex
expressions and advanced usage.
.SH NOTES
Differences to \fIr.mapcalc\fR module:
.RS 4n
.IP \(bu 4n
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, ...).
.IP \(bu 4n
The output raster name is not included in the expression.
.IP \(bu 4n
The expression is expected to be a single short one liner
without the function eval().
.RE
Differences to \fIr.mapcalc.simple\fR module in GRASS GIS 5 and 6:
.RS 4n
.IP \(bu 4n
The primary purpose is not being a GUI front end to
\fIr.mapcalc\fR, but a wrapper which allows easy building of
interfaces to \fIr.mapcalc\fR (including GUIs).
.IP \(bu 4n
Whitespace (most notably spaces) are allowed
(in the same way as for \fIr.mapcalc\fR).
.IP \(bu 4n
The variable names are case\-insensitive to allow the original
uppercase as well as lowercase as in option names
(unless the \fB\-c\fR flag is used).
.IP \(bu 4n
Option names for each map are just one letter (not amap, etc.).
.IP \(bu 4n
Output option name is \fBoutput\fR as for other modules
(not outfile).
.IP \(bu 4n
Raster map names can be optionally quoted (the \fB\-q\fR flag).
.IP \(bu 4n
There is no expert mode
(which was just running \fIr.mapcalc\fR).
.IP \(bu 4n
The \fBexpression\fR option is first, so it is possible to
omit its name in the command line
(just like with \fIr.mapcalc\fR).
.IP \(bu 4n
Overwriting of outputs is done in the same way as with other
modules, so there is no flag to not overwrite outputs.
.RE
.SH EXAMPLES
.SS Basic examples
.br
.nf
\fC
r.mapcalc.simple expression=\(dq0\(dq output=zeros
r.mapcalc.simple expression=\(dq1\(dq output=ones
r.mapcalc.simple expression=\(dq2\(dq output=twos
\fR
.fi
.br
.nf
\fC
r.mapcalc.simple expression=\(dqA + B + C\(dq a=zeros b=ones c=twos output=result1
\fR
.fi
.br
.nf
\fC
r.mapcalc.simple expression=\(dq(A * B) / 2 + 3 * C\(dq a=zeros b=ones c=twos output=result2
\fR
.fi
.br
\fIFigure: r.mapcalc.simple graphical user interface\fR
.SS Example expressions
Addition:
.br
.nf
\fC
A + B
\fR
.fi
No spaces around operators are not recommended for readability,
but allowed in the expression:
.br
.nf
\fC
A+B
\fR
.fi
More complex expression with a function:
.PP
.br
.nf
\fC
exp(A+C)+(B\-2)*7
\fR
.fi
.SH SEE ALSO
\fI
r.mapcalc,
r3.mapcalc,
t.rast.mapcalc,
g.region
\fR
.SH AUTHORS
Vaclav Petras, NCSU GeoForAll Lab
.br
Michael Barton, Arizona State University (updated to GRASS 5.7)
.br
R. Brunzema (original 5.0 Bash version)
.SH SOURCE CODE
.PP
Available at: r.mapcalc.simple source code (history)
.PP
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.PP
© 2003\-2020
GRASS Development Team,
GRASS GIS 7.8.5 Reference Manual