December 15, 2015
By George Demmy
TerraGo just released version 6.8.2 of its core GeoPDF-oriented product suite. Usually these sorts of dot dot releases don’t call for much comment, but this release, in combination with some other factors, has me thinking about a couple different things.
The first is how much going on under the hood is being represented by so little in the incrementing of a third-place digit in the version string. Yet, from a compatibility feature/function perspective, this really is only a dot dot release. We’ve made some very nice performance improvements in both speed and size of resulting GeoPDF in Publisher, so everybody should definitely run out and get the latest release. PubPy works the same, only better. Toolbar and Composer have some nice bug fixes (I’ll confess – the software has a bug or two) and play nicer with Adobe’s updated UI in Acrobat DC. This is a compelling release, even if there are no new functions or features.
The idea of stuff going on under the hood away from casual inspection got me thinking about the PDFs we create with Publisher versus PDFs created with other software. Normally, I don’t like to get in to discussions about ours versus theirs PDFs, because the conversations tend to focus on details that I generally find irrelevant or uninteresting. I prefer to focus on what you can do with them, and that more often than not is about software, not bits and bytes in a file. That said, in many cases, the PDF documents we create with Publisher are simply more useful, more accessible, and easier to use than their non-TerraGo cousins. One case in point is how we arrange the object data inside the PDF to store feature attributes so that a single feature can be selected with a single click, whereas a more conventional arrangement will have Reader select the class, then subclass, so on, frequently requiring two, three, or even more clicks to arrive at the feature in which you’re interested. There are other things that our GeoPDF maps do that other PDF maps even without our software, but the thing that’s hard to put into marketing collateral is what our software does is not make a better PDF (which it can and often does by default) but rather that our software enables you to make the map and experience you want and not be forced to take whatever an “exporter” feeds you. Publish versus export. Author versus button-pushing exporter.
Which brings me to another point. Over lunch, I was having a discussion with a co-worker who thought it was knuckle-dragging dumb that source code was stored as text. He thought it should be sorted as byte-code or some other format-independent medium and displayed according to the taste of the reader. Well, although I am mostly ambivalent about two spaces versus four and where the brackets go (we have formatters for that), I recoiled at the idea of having an element of expressiveness stripped away. This is not for any artistic reason, but rather because I believe that source code should primarily be written for other programmers and secondarily to be executed by computers. Anything that can strip away the effectiveness of communication should be approached with great caution. As Abelson and Sussman say in the preface to their classic Structure and Interpretation of Computer Programs:
First, we want to establish the idea that a computer language is not just a way of getting a computer to perform operations but rather that it is a novel formal medium for expressing ideas about methodology. Thus, programs must be written for people to read, and only incidentally for machines to execute.
So, what does a geeky computer science quote from the hairiest text this side of Knuth’s The Art of Computer Programming have to do with Publisher, PDF, GeoPDF, exporters and the like, for all love?
Maps aren’t just for looking at, although that’s the way many, if not most, people use them. Maps are a novel medium for communicating information about relationships of things in space. Publisher simply gives you much greater control over what you publish versus rote export. Delivering GeoPDF maps to users with Toolbar provides a novel medium for communicating all sorts of information as interactive, geographically-enabled applications, rather than just a picture. ArcMap invites you to take all your hard work and make a picture. Publisher invites you to communicate the results, significance, and meaning of your work as a GeoPDF application. Never squander an opportunity to deliver a GIS-lite application by sending a PDF to do GeoPDF’s job.