Markus wrote:
I have added a new "eps=" parameter to d.polar. This
writes the output to an EPS file instead of launching
'xgraph' (which isn't available on all systems by default).
Description:
Draws polar diagram of angle map such as aspect or flow directions
Usage:
d.polar map=name [undef=value] [eps=string]
Parameters:
map Name of raster angle map
undef Pixel value to be interpreted as undefined (different from NULL)
eps Name of optional EPS output file
My colleague Brune Caprile wrote a LISP program for
me to generate the EPS code from the d.polar raw data,
I rewrite it to SHELL 
Now you can generate high quality polar diagrams.
(great!)
It would be nice if the xgraph part could be changed to use d.graph,
here is a start:
RADIUS_COEFF=`echo "$TOTALNUMBER $TOTALVALIDNUMBER $MAXRADIUS" | \
awk '{printf "%.8f", $1/$2 * $3}'`
# ${TMP}_sine_cosine_replic
# ${TMP}_vector
# ${TMP}_outercircle
RING=0.95
cat ${TMP}_sine_cosine_replic | tail +2 | awk -v RING=$RING -v MAX=$MAXRADIUS \
'{printf "%f %f\n", (($1 / MAX * RING) +1)*50, (($2 / MAX * RING)+1)*50}' \
> ${TMP}_sine_cosine_replic_normalized
VECT=`cat ${TMP}_vector | tail -n 1 | awk -v RING=$RING -v MAX=$MAXRADIUS \
'{printf "%f %f\n", (($1 / MAX * RING) +1)*50, (($2 / MAX * RING)+1)*50}'`
d.erase
d.graph << EOF
# draw the goods
color red
polygon
`cat ${TMP}_sine_cosine_replic_normalized`
# draw axes
color black
width 0
move 0 50
draw 100 50
move 50 0
draw 50 100
# draw circle
# mandatory as drawing proportional to non-square frame
# draw vector
color green
width 2
move 50 50
draw $VECT
# draw compass text
color black
width 2
move 50.5 95
text N
# move 50.5 1
# text S
# move 1 50.5
# text W
# move 95 50.5
# text E
EOF
Hamish