[GRASSLIST:283] RE: r.mapcalc puzzler

[H Bowman]

> > Don't you need quotes around a complicated expression like that?
> > I've always used %> r.mapcalc "a=sin(b)+cos(c)" so that the special
> > characters don't throw the shell into a tizzy.


Not if it is within a << EOF .. EOF; it treats whatever's inside as if
it were a file on the disk. Using ""s are necessary to protect the () *
etc from being interpreted as part of the command, ''s are even more
restrictive and stop $SHELL_VARIABLES from being expanded. 

I think my problem was cutting and pasting between a Debian xterm and a
RedHat9 one. Redhat's gone and changed all their language encoding
around, and I think ASCII tabs get interpreted as special characters in
whatever Unicode system they now use..??


> 
> which includes the following mapcalc magic to do a better r.grow:
> 
> r.mapcalc << EOF
>  grown = if(      $src,       $src,		\\
> 	 if($src[0,-1], $src[0,-1],      \\
> 	  if( $src[0,1],  $src[0,1],	  \\
> 	   if($src[-1,0], $src[-1,0],      \\
> 	    if( $src[1,0],  $src[1,0]       \\
> 	)))))
> EOF