PCPlus 292: The science of route planning

By March 2010, I was starting to move to a more “how it works” style of article to go along with changes in the magazine, rather than a “layman’s guide to algorithms” article which I’d traditionally done. This article on GPS systems (or sat-nav, if you’re in England) was my first real attempt at such an article: select some technology and explain its underpinnings for the lay audience.

At this remove, I can’t remember why I chose GPS to write about, but I will say I did buy myself a Garmin nüvi 265W first, just for the research. Don’t want to pull the wool over anyone’s eyes here; it really wasn’t for personal reasons. There: just wanted to clear that up.

Anyway, it was all rather fun to write. I started off with how GPS units get and process the signal from the satellites, and then moved on to the A* algorithm (yes, I had to include an algorithm) and how it was used to determine shortest routes given a map. Of course, I also had to talk about how the map was stored as a series of vectors, and so on. As an example, I showed off our neighborhood as a GPS-style map and discussed how to get from the northeast-most corner to the southwest-most corner.

All in all, I really liked the way this article turned out. Sometimes writing them can be a bear and the words have to be dragged out of me, but this one turned out real smooth. And the Powers That Be liked it too: it was republished on the web by PC Plus’ sister company techradar.com just after print publication here.

This article first appeared in issue 292, March 2010.

You can read the PDF here.

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2 Responses

#1 Keith Miller said...

07-Apr-11 12:37 PM

Very interesting article, thanks!

For some reason the link doesn't work in Chrome or Firefox 4. I had to resort to IE.

#2 julian m bucknall said...

01-May-11 4:24 PM

Keith: Very puzzled. Works for me in the latest versions of the four major browsers. It's just a link to my folder on Amazon S3 and all the access permissions are properly set.

Cheers, Julian

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