George Demmy wrote:
| -----Original Message-----
| From: Brent Fraser [mailto:[email protected]]
| Sent: Thursday, February 05, 2009 10:45 PM
|
| I haven't read the spec yet, but I think GDAL would require linking
| to a library capable of writing (and maybe reading) PDF frames and
| tags. I don't know of any Open Source PDF library that can to that
| yet (maybe PoDoFo). Do you know of any?
For rote "conversion", to which GDAL is well suited, wrapping a raster
image in PDF clothing is a fairly simple exercise, so a full-blown
library isn't necessary. With vector data, you have symbolization
issues, font issues, etc. One option would be to use PostScript as an
intermediate, and use Ghostscript to handle the PDF bits, and
post-process the PDF file to add the geospatial bits.
Creating the graphics (raster or vector) portion of a PDF is relatively easy, with several Open Source PDF libraries to choose from. MapServer has been doing it for years and hopefully will do an even better job of it in the coming months. The part I'm grappling with is the geospatial bit.
<Here's some background for others reading this:>
Terrago's GeoPDF encodes the spatial reference system information required for
the geospatial bit in PDF tags linked to PDF frames (page regions). I think.
</>
I'd like to add geospatial information to PDFs (using frames and tags looks like an elegant approach), but I can't find an Open Source PDF library that does fames and tags. And I'd prefer to be compatible with Terrago's GeoPDF (and now Adobe's too?). For those interested in Adobe's method, read pages 49 to 54 of http://www.adobe.com/devnet/acrobat/pdfs/adobe_supplement_iso32000.pdf
Brent Fraser
| That said, I'd like to see the Open Source GeoPDF effort go
| forward; I think there's very good value there...
You and me both!
| Brent Fraser
G
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