scale problem using ppm-files

[Sven Fuhrmann]

Dear GRASS-users,

	I have a little scale problem in GRASS4.1 and I hope you will be
able to help me. 

	I have access to a Canon CLC 10 Color Laser Printer (Canon IPU) 
which has a dpi of 400x400. Unfortunately I do not have a Canon CLC 10
driver. In order to solve this problem I do create a ppm-file in GRASS
using p.map. In a second step the ppm-file will be transformed to a 
postscript-file using the ppmtops command under pbmplus (written by
Joe Postkanzer).

As you know, there is a driver.sh for the ppm-command and i set it up as
following :

:


HRES=400.0
VRES=400.0
NCHARS=1

TEXTSCALE=1
TEXTFUDGE=0
TEXTSPACE=1
BLOCKSIZE=1
BLOCKSPACE=1
NBLOCKS=1

MAPLP=${MAPLP-$HOME/paint.ppm}
WIDTH=2000
HEIGHT=2000
cp /dev/null $MAPLP
export HRES VRES NCHARS MAPLP WIDTH HEIGHT
export TEXTSCALE TEXTSPACE TEXTFUDGE BLOCKSIZE BLOCKSPACE NBLOCKS

exec ${PAINT_DRIVER?}


	In a next step I ran p.map in GRASS, using a 10x10 pixelmap, res:30m 
and a 1:25000 scale):


                         REGION FACILITY
LOCATION: spearfish                                MAPSET: sven

CURRENT REGION: N=4921000  S=4920700  RES=30  ROWS=10
                E= 591300  W= 591000  RES=30  COLS=10
PROJECTION: 1 (UTM)
ZONE:       13

-------------------------


PAINTER:    ppm
LOCATION:   spearfish
MAPSET:     sven
MASK:       none

RASTER:     elevation in PERMANENT
COLORMODE:  best
VECTORS:    (none)
SITES:      (none)
LABELS:     (none)
SCALE:      1:25000
GRID:       100 meter, numbered



As a result I got a 12MB paint.ppm file with a pixelcount of 2000x2000 cells.

I did change the maximum width and height in the driver.sh and still: the
pixelcount in the ppm file always changed to the maximum number of cells.
In fact, the scale I wrote down in p.map was not achieved.
The read.me file in GRASS does not give me a hint where to look for in order
to solve this probem.

READ.me file in GRASS:

>The maximum width and height of the output is set in Driver.sh as the
>variables HEIGHT and WIDTH. You can change these if you wish.  I have
>not figured out what combinations are good. No matter what values you
>pick some window sizes will fit better than others.


I did transform those ppm-files into postscript format and I could see that
the size of the printout had something to do with the width and height
changed in the driver.sh. but still: I do not get the right scale.

I would appreciate any help in order to solve this problem


Thank you,
Sven Fuhrmann