Saturday, August 6, 2011

Our map may not quite match the territory

A map should let us see where we’re going and how to get there. Back in June I spoke in Salt Lake City. Most of that metro area is easy to navigate, because the streets are marked in a logical grid system. The area around the University of Utah and old Fort Douglas is an exception. On the morning of June 14th I set off with a city map on my lap for my destination in the University research park. It showed me that East 500 South became South Foothill Drive, which turned to run southeast. I needed to get in a left turn lane for Wakara Way, follow it into the research park, and then turn right onto Chipeta Way.

Oops! I turned one light too soon and wound up on South Wasatch Drive. My map said I could just turn right and get over to South Connor Road, which would become Chipeta Way. Wrong! That area had University of Utah housing, so many streets now were dead-ends. My first turn led me into a parking lot, which gave me a place to stop and recheck the map. My second try led me a few blocks further - into another parking lot. On my third try I finally found a through street that led over to my destination. Fortunately I’d allowed extra time to get through downtown (which turned out not to be a problem), and I still arrived early.

Sometimes our map might even be wrong on purpose. When I was growing up in Pittsburgh I noticed that the city map from Gulf Oil always contained a fictitious road connection in Schenley Park between Schenley Drive and the middle of a horseshoe bend on E. Circuit Road. It probably was one of a set of errors for letting them detect if someone had copied their map.

Back when I was a student the printed directory for Carnegie Mellon University used to contain a set of phony names with real addresses, and phony addresses with real names. Those features were for detecting who was reselling it as a commercial mailing list. One of my friends was renamed Wadza Duckworth, and another had his computer science department address relisted as being a tiny, always-locked equipment access closet within a room in Wean Hall. Any time those ringers got mail the sender got a cease-and-desist letter from an attorney.

The previous two paragraphs began as comments to a blog post by Scott Berkun on missing maps and the fragility of technology. He reused them in a post on how to use bad data for good, and now did I too.

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