two colored output needed

[Manfred Zerndl]

Hi List,

i have some raster tiles in TIFF format.
gdalinfo tells me the following:

------- begin -- gdalinfo -----
Driver: GTiff/GeoTIFF
Size is 13000, 13000
Coordinate System is `'
Origin = (4526459.127166650258005,5316969.772833350114524)
Pixel Size = (0.211666700000000,-0.211666700000000)
Metadata:
 TIFFTAG_DOCUMENTNAME=Standard Input
 TIFFTAG_IMAGEDESCRIPTION=converted PNM file
 TIFFTAG_RESOLUTIONUNIT=2 (pixels/inch)
Image Structure Metadata:
 COMPRESSION=CCITTFAX4
Corner Coordinates:
Upper Left  ( 4526459.127, 5316969.773)
Lower Left  ( 4526459.127, 5314218.106)
Upper Right ( 4529210.794, 5316969.773)
Lower Right ( 4529210.794, 5314218.106)
Center      ( 4527834.961, 5315593.939)
Band 1 Block=13000x1 Type=Byte, ColorInterp=Palette
 Metadata:
   NBITS=1
 Color Table (RGB with 2 entries)
   0: 255,255,255,255
   1: 0,0,0,255
---- end -- gdainfo -----


I have defined following outputformat in th mapfile:

OUTPUTFORMAT
       NAME HLTIFF
       DRIVER "GDAL/GTiff"
       EXTENSION "tif"
       MIMETYPE "image/tif"
       IMAGEMODE PC256
       FORMATOPTION "QUANTIZE_FORCE=ON"
       FORMATOPTION "QUANTIZE_DITHER=OFF"
       FORMATOPTION "QUANTIZE_COLORS=2"
       FORMATOPTION "COMPRESS=GROUP4"
END

When I create a tileindex for mapserver then the response tile  has a 
color table
with many colors entries, but only two colors are needed.
So the file is bigger than necessary.
Maybe I need some kind of "IMAGEMODE  PC2" but this is not possible.

How can i force mapserver to generate two-colored tiles?
It is not important what format the genereted tile is
(PNG or JPEG would be nice, but TIFF is also ok).


Best Regards,

Manfred Zerndl