NAME
mapcalculator.sh - TCLTK-Frontend for r.mapcalc
SYNOPSIS
mapcalculator.sh
[help=[help,man]]
[expert=expert]
A_MAP=[map
] B_MAP=[map]...
DESCRIPTION
mapcalculator.sh
is a bash-script usally called via mapcalculator in TCLTKGRASS. It creates a r.mapcalc call
from the parameters you choose in mapcalculator. If you want to use mapcalc on the commandline you
should use the original r.mapcalc command.
In TCLTKGRASS you can choose up to six
maps [entries A - F] to be included in the calculation. Then you have
to enter a formula and a name for the resulting raster map. You won't receive
a warning, if you choose the name of an allready existing raster map,
but you can protect your files from overwriting by activating the appropriate
checkbox.
You can create a calculation formula in the field formula
like this:
A+C or (more complex:) exp(A+C)+(B-2)*7.
A, B, C, etc. are your
choosen raster maps. You must not insert the output file:
Right: A+B
Wrong: newfile = A+ B
Use no blanks! Blanks are inserted by the
script to devide the map names from the rest of the formula.
The script won't check the syntax or logic of the formula and you will only receive
the error messages from r.mapcalc, if anything went wrong.
For details on creating a formula see the r.mapcalc manual page (man r.mapcalc).
BUGS
It is not possible to choose maps from different mapsets with the
raster button. But you can choose maps from different mapsets by entering
the name map@mapset in any of the map fields [A-E].
You may have difficulties
to calculate formulas containing neighborhood modifier. The only way to
use neighborhood modifier is entring them directly into the formula field:
A+B*map_with_modifier\[x,y\]
where map_with_modifier is the name of your
map. The name of your map should not contain any uppercase A - F, because they will be interpreted as raster
map entries. Don't forget to mask the brackets with backslashes, or you will receive
errormessages form TCLTKGRASS.
SEE ALSO
r.mapcalc
AUTHOR
R. Brunzema
Last changed: $Date$