Kristian (and all),
Back in 2005 I challenged one of our new engineers to create a 34 inch by 44 inch PDF map (with a graticule!) of a
satellite image using Mapserver (v4.6). There were several problems, the most serious in mappdf.c which uses an 8-bit
GD library image format restricting the images inserted into the PDF to 8 bit only (although just prior to insertion
they're converted to JPEG, a 24-bit format!).
One of the other problems was memory usage. Mapserver creates two or three copies of the image when rendering it to
PDF (and at 300 dpi an RGB image of that size can be 500 mb). But if your format is smaller than 34 x 44, it may not be
a problem.
If there's enough interest, I'd be willing to contribute the code changes he made if there's a Mapserver
developer/committer willing to review, upgrade them to v5,and test (and it may require an RFC as there was a map file
addition to OUTPUTFORMAT/FORMATOPTIONS, I think).
Brent Fraser
Kristian Thy wrote:
On Thu, Apr 24, Flavio Hendry wrote:
Discussed the issue a while ago with Frank Warmerdam. He had less
problems on a LINUX System running on a 64bit machine (he supposes it
could go as high as 25'000 pixels). On Windows 32 it bangs at around
10'000 to 14'000 pixels depending on content. Did not try on Windows 64.
Thanks to advice from the list, I now have huge orthophoto pdfs. But now
I have another problem - using png output, I get nice 24 bit images, but
my pdf output is dithered 8 bit. The relevant part of my map file:
IMAGETYPE png24
OUTPUTFORMAT
NAME png
MIMETYPE "image/png"
DRIVER AGG/PNG
EXTENSION png
IMAGEMODE RGB
TRANSPARENT FALSE
END #outputformat
OUTPUTFORMAT
NAME pdf
MIMETYPE "application/x-pdf"
DRIVER pdf
EXTENSION pdf
IMAGEMODE RGB
FORMATOPTION "OUTPUT_TYPE=RASTER"
TRANSPARENT FALSE
END #outputformat
Removing the FORMATOPTION makes no difference.
http://quovadis.dk/dl/ortho.png
http://quovadis.dk/dl/ortho.pdf
The commandline incantation used to produce the images:
$ shp2img -m ddo.map -o ortho.pdf -s 1654 1169 -l DDO -e 659000 6058000
663200 6060970 -i pdf
Does the pdf driver support 24 bit at all? Can I do 24 bit pngs and
assemble the pdfs by hand?
\\kristian
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