In article <{BCT-PGOTFE}@bnr.ca> you wrote:
: I am looking for a means of automating the classification of stream
: segments by "order". An "Order 1" stream is one that has no other
: stream flowing into it. An "Order 2" stream is one that is formed by
: the junction of two "Order 1" streams, etc. Can anyone suggest a
: GRASS routine that could be used to solve this problem?
What you want to do is to classify a stream net in a Strahler stream order,
I suppose. To get this classification, you can use the GRASS module
r.watershed armsed=... the output armsed file is a text file, which
determines the stream segments, that flow in each stream segments (The
stream segments are the output of the r.watershed streams=... option).
I have written a shellscript, which calculates out of this text file the
strahler order of the segments, perhaps you can use it, but no warranties:
#!/bin/sh
if [ ! "$GISRC" ]
then
echo "Sorry, you are not running GRASS"
exit 1
fi
#
# Shellscript, was aus dem output von r.watershed
# eine Ordnung nach Strahler erzeugt
#
myname=`basename $0`
usage()
{
echo
echo "USAGE: ${myname} input=name armsed=name output=name"
echo " input - input rastermap with streams or basins"
echo " armsed - output-file of r.watershed"
echo " output - output rastermap with strahler-ordering "
echo
exit 1
}
# Bezeichnung der temporaeren Files
temp1=`g.tempfile pid=$$`
temp2=`g.tempfile pid=$$`
temp3=`g.tempfile pid=$$`
trap 'rm -f $temp1 $temp2 $temp3'
# Eingabe ueberpruefen
if [ $# -eq 0 ]
then
g.ask type=old prompt="inputmap:" element=cell desc="raster" unixfile=/tmp/
$$
. /tmp/$$
rm -f /tmp/$$
if [ ! "$name" ]
then exit 0
fi
MAP=$name
echo
echo "output rastermap"
echo "Hit RETURN to cancel request"
echo
OUT=`line`
if [ ! "$OUT" ]
then exit 0
fi
echo
echo "input armsed-file"
echo "Hit RETURN to cancel request"
echo
IN=`line`
if [ ! "$IN" ]
then exit 0
fi
else
# Ueberpruefung der maps
if [ $# -ne 3 ]
then
usage
fi
# test for correct form of arguments
if [ `echo $1 | cut -c1-6` != "input=" -o `echo $2 | cut -c1-7` != "armsed="
-o `echo $3 | cut -c1-7` != "output=" ]
then
usage
fi
# put args into named variables
MAP=`echo $1 | cut -c7-`
IN=`echo $2 | cut -c8-`
OUT=`echo $3 | cut -c8-`
eval `g.findfile element=cell file="$MAP"`
if [ ! "$file" ]
then
echo $MAP": illegal mapname"
exit 0
fi
fi
# Erzeugung der Hilfsdatei
# Format: EZG-nr Nummern der Gebiete, die in EZG entwaessern
rm -f $temp1
for i in `awk '{print $1}' $IN`
do
awk 'BEGIN{printf("%d ",'$i')} {if($4=='$i') printf("%d ",$1)} END{printf("\n")
}' $IN>> $temp1
done
# Extraktion der Ordnungen aus der Hilfsdatei
rm -f $temp3
while [ `wc -l $temp1|awk '{print $1}'` != 0 ]
do
nawk '
NF==1{print $1" = 1">>"'$temp3'"}
NF>=4{print "Es sind uneindeutige Verzweigungen vorhanden" >"/dev/tty"; exit 6
}
NF>1&&NF<4{s=$1
i1=$2
i2=$3
while(getline <"'$temp3'") {if($1==i1) {o1=$3; break} else o1=0}
close("'$temp3'")
while(getline <"'$temp3'") {if($1==i2) {o2=$3; break} else o2=0}
close("'$temp3'")
if(o1==0 || o2==0) {print s,i1,i2; next}
if(o2==o1) {print s" = "o1+1>>"'$temp3'"}
if(o2>o1) {print s" = "o2>>"'$temp3'"}
if(o1>o2) {print s" = "o1>>"'$temp3'"}
}' $temp1 >$temp2
if [ `echo $?` = "6" ]
then exit 0
fi
mv $temp2 $temp1
done
# Erzeugung der output Map
r.reclass i=$MAP o=$OUT<$temp3
exit 0
Have fun with that hack, Jochen