[GRASSLIST:5026] Re: Looking for something like r.grow, but that retains value

[Patrick Dunlavey]

Here's a shell script I wrote to do exactly this.

-- Pat

<DEFANGED_Script>

echo ""
echo Grow into zero cells v0003
g.ask type=old element=cell desc=raster prompt="Enter source file"
unixfile=/tmp/$$ eval `cat /tmp/$$` rm -f /tmp/$$ if [ ! "$file" ] then
    exit 0
fi
src="${fullname}"

echo "$src"

gotit=0
while test $gotit -eq 0
do
	echo -n "iterations: "
	read itrs
	if test $itrs -ge 1 -a $itrs -lt 30
	then
		gotit=1
	else
		echo Sorry, iterations must be greater than 0  and less
than 30
	fi
done

echo ""
echo Running r.mapcalc, please stand by.
echo Your new map will be named grown.  Please consider renaming. echo
""

# Note: no space allowed after \\:
 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

#Remove nulls created at edges
r.mapcalc 'grown=if(isnull(grown),0,grown)'

	echo "iteration=1"

 i=2
 while [ $i -le $itrs ]
 do
r.mapcalc << EOF
	grown = if(      grown,       grown,		\\
		 if(grown[0,-1], grown[0,-1],      \\
	 	  if( grown[0,1],  grown[0,1],	  \\
	  	   if(grown[-1,0], grown[-1,0],      \\
	   	    if( grown[1,0],  grown[1,0]       \\
		)))))
EOF

#Remove nulls created at edges
r.mapcalc 'grown=if(isnull(grown),0,grown)'
	echo "iteration=$i"
	let i=$i+1
done


echo ""
echo New map created and named grown.  Consider renaming

</Script>