[Geowanking] GeoPDF 2.2 has been approved by OGC as best practice
bfraser at geoanalytic.com
Fri Feb 6 08:53:38 PST 2009
George Demmy wrote:
> | -----Original Message-----
> | From: Brent Fraser [mailto:bfraser at geoanalytic.com]
> | 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
> | 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
More information about the Geowanking