Friday, August 15, 2014

PDFs get Geospatial

Printing Geospatial PDFs that can be used in programs like Avenza PDF Maps is an oft-requested feature that's been hanging over my head for some time.  Having looked into it and abandoned the effort, I've lived life dreading the prospect of wading back into the fray.  However I took another crack at it this week and, armed with a better understanding of the PDF spec, it turned out not to be so bad.

Starting now, all single-page PDFs generated by CalTopo are Geospatial PDFs.  Edit: Looks like I jumped the gun a bit.  There were some compatibility issues with the iOS version of Avenza that have now been fixed.

Complementing this is a new short-URL feature that makes it easier to share CalTopo PDFs or load them onto a phone.  Step 1 is, as usual, to click Print and then Create a PDF:

Underneath the Generate PDF button is a new Generate Link button.  This behaves just like Generate PDF, but instead a new browser tab opening with a long query string or a blank form post, it opens with a short URL.

Anyone with this URL can now download your PDF; no need to save it to a computer and then share using a 3rd part hosting service.  While the print page indicates that links expire in 30 days, I may keep them around longer if they don't occupy too much space - currently I have to go in and purge them manually.

The only reason for a separate Generate Link button is to avoid cluttering my database with PDFs that will never be shared.  If that proves to be a non-issue, I'll merge them into one button that always generates a short URL.

I have no affiliation with Avenza, but their free PDF Maps app allows you to import directly from the CalTopo URL: