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Friday, September 26, 2008

Why Open GeoPDF Now?

I've been asked here and elsewhere, "what is the link between the submission of GeoPDF to OGC and Adobe's geospatial extensions in Acrobat and Reader 9.0?" There is a link, to be sure, but the primary reason that TerraGo has submitted its legacy georegistration technique to OGC is our customers demanded it. There are terabytes (petabytes?) of GeoPDF files out there that use the technique and they wanted to be confident that their investment was secure. That's quite reasonable by any measure. It would be one thing to just post a specification for the technique, a la ESRI's shape file spec [PDF], but wouldn't carry the imprimatur of a standards organization that our customers demand.

So, where does that leave folks who want to make geospatial PDF files? That depends. If you have PDFs that you want to make geospatial, you can use Acrobat Pro Extended 9.0 (APEX) or Map2PDF for Acrobat installed in some flavor of Acrobat. The benefit of using Map2PDF is that you gain access to the geospatial functionality available in the free GeoPDF Toolbar. This is an important point: GeoPDF is *not* about a georegistration technique -- we'll be using ISO32000 under-the-hood going forward as well as supporting the legacy format. GeoPDF can use either. GeoPDF is all about configuring maps and data to be used by the free Toolbar to actually do something.

If you have ArcGIS 9.3 and the Adobe's functionality is sufficient, you can get ESRI's geospatial PDF extension. If you want to access GeoPDF Toolbar functionality and finer control over the PDF creation process, then you'll need Map2PDF. In principle, you could use ESRI's extension with Map2PDF for Acrobat to create GeoPDF files that use the proposed ISO extensions for georegistration...

For the ambitious, you can get the PDF spec, er purchase ISO 32000, snarf Adobe's proposed extensions to ISO 32000 and roll your own. These could be used by Map2PDF for Acrobat to create GeoPDF files suitable for use by the GeoPDF toolbar, just like files created by APEX, or files created by ESRI 9.3...

The question remains, why didn't we do this sooner? That's a question best answered over a cold beer. Personally, I'm delighted to see georegistration open, published, and free to use in PDF files. It's what I've been working toward for many years, and Adobe and ESRI have vindicated this effort.


Anonymous Anonymous said...

I've been comparing the TerraGo Technologies GeoPDF spec provided to OGC for adoption as a "best practice" with the Adobe geospatial registration spec in PDF 1.7, extension level 3.

They seem to provide the same function, but not the same way.

I'm not sure that the community needs two specs.

What am I missing?

4:58 PM EST

Blogger George Demmy said...

Dear anonymous,

I hope this post helps answer your timely and important question. Thanks for reading!


6:29 PM EST

Blogger George Demmy said...

Update:The OGC has posted the best practice on their best practice page.

9:16 AM EDT


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