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Tuesday, August 05, 2008

Properly Printing Portable Documents

Those of you who know and use GeoPDF technology for producing high-quality maps from ArcGIS have probably ended up with low resolution background imagery at some point or another. This happens even though you have 1 foot pixel or better aerial photography that you would otherwise expect to see someone sitting on a park bench. Why is that? ArcGIS uses a print driver to produce PDFs which means that you have to account for dots per inch (DPI) rather than the actual spatial resolution (GSD) of your input data. Hopfully these next few steps will help you produce better GeoPDFs...
  1. In ArcGIS, select File --> Page and Print Setup
  2. Find the total rows and total columns for your input image and divide each by your default DPI. For example, my NAIP image for Cobb County GA is 10000 x 15000 pixels. (10000/300 DPI and 15000/300 DPI) == 33.33 inches x 50 inches.

  3. Save the settings and export your data from Map2PDF for ArcGIS and you will see a GeoPDF that is pretty close to the resolution of your input data set...

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Blogger LeeOnCandler said...

If you want to go the other way and have full resolution imagery for a given page size, you'll need to divide by the dimensions of your printable bounds.

To use your example for a 11" x 17" page: (10000/10" and 15000/15") = 1000 DPI. Just fill in this resolution when you export the GeoPDF and you'll get your imagery in full "park benchy" detail.

11:14 AM EDT


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