classy reclassing

[Greg Koerper]

Here's a simple shell script that is helpful for streamlining the r.reclass
command when applied to continuous variables.  It labels the reclass
categories, which simplifies legend display.  It has an offset option that
allows for manipulation of negative values.  If you use the -N flag, you can
quickly ascertain how it builds reclass rules.  We've used it for post-
processing of model output of continuous variables associated with sites.

-------------------------------shell script ---------------------------------
#! /bin/sh

# reclass.sh takes a single line of input which specifies the beginning
#   range of each of a series of range intervals that are then passed to
#   r.reclass as input.  The units_abbrev is helpful in outputting a legend.
#   Use offset if the cell file data are all positive but in fact may represent
#   negative values (useful in avoiding "no data" designations for real 0
#   values).

# comments, concerns to greg at bio.cor2.epa.gov

# if -N flag, raster is not created and input to r.reclass is
#  stored under given file_name

# if -c flag, next argument specifies color rules for reclassification
#  see r.colors (incompatible with -N)

USAGE="$0 [-N | -c color_rules] file units_abbrev [offset] [< input]"
RASTER="YES"
COLORS=''

if [ $# -eq 0 -o $# -gt 5 ]
then
	echo $USAGE
	exit -1
fi

# continue only if user is executing GRASS 

if [ "$GISRC" = "" ]
    then
        echo "Sorry, you are not running GRASS" >&2
        exit 4
    else
        USERGRASS="$GISDBASE/$LOCATION_NAME/$MAPSET"
fi

if [ $1 = "-N" ]
then
    RASTER="NO"
    shift
    RULES=$1
elif [ $1 = "-c" ]
then
    COLORS=$2
    shift 2
fi

if [ $RASTER = "YES" ]
then
    RULES="/tmp/tmp.$$"
    FILE=$1
fi

units=$2
cat=`expr 1`
if test $3
then
	offset=`expr $3`
else
	offset=`expr 0`
fi

read cuts
echo "  OK, I'll take it from here . . ."
set -- ${cuts}
start=$1
shift

cp /dev/null $RULES

while test $1
do
	RANGE=`echo "${start} thru $1 = ${cat}  "`
	echo $RANGE`expr $start + $offset` - `expr $1 + $offset` ${units} \
	 >> $RULES
	start=`expr $1 + 1`
	shift
	cat=`expr $cat + 1`
done
echo "end" >> $RULES

if [ $RASTER = "YES" ]
then [ -s $USERGRASS/colr/$FILE.rec ] && rm $USERGRASS/colr/$FILE.rec
    r.reclass input=$FILE output=$FILE.rec < $RULES
    rm $RULES
    if [ $COLORS ]
    then
	r.colors map=$FILE.rec color=rules < $COLORS
    fi
fi

----------------------------end shell script----------------------------------
greg

******************************************************************************
Greg Koerper                            Internet: greg at towhee.cor2.epa.gov
ManTech Environmental Technology, Inc.  UUCP:     hplabs!hp-pcd!orstcs!koerper
200 SW 35th St., JSB                    
Corvallis, OR   97333           "The 90s will make the 60s look like the 50s. 
(503) 754-4490                          Just ask your kids."
 fax:  (503) 754-4338
******************************************************************************