My wife is preparing for one of her annual open studio events, and asked me to update her website with an announcement and a map. I’ve done this before, so it’s odd I never noticed that none of the popular mapping services accurately pinpoints our address. In Google Maps, the pushpin is stuck near Douglass St., a little more than a block away from the Roxbury/Grant intersection where we really are:

Live Maps gets the location right, but it shows a Roxbury/Hardy Ct. intersection that does not exist.

Long ago, we believe that Hardy Ct. did join Roxbury St, but at some point that changed and now it’s a dead end as shown correctly in Google Maps.

Yahoo Maps, like Live Maps, has the correct location but wrong street layout:

What to do? I tried adjusting the lat/lon parameters in the Google Maps URL in order to move the pushpin to the correct location. That turned out to be more trouble than it was worth, so I just took a picture of a map, stuck a marker in the right place, and published that.

Along the way, I noticed a few things about these online maps that I’ve never considered before. First, in all these applications, it’s harder to work directly with lat/lon coordinates than I would have thought. Everything’s geared toward street addresses, which makes sense most of the time for most people. But as GPS coordinates become commonly available, shouldn’t they be first-class citizens in these user interfaces?

More broadly, there’s the question of ground truthing — the subject of a wonderful New Yorker article. The reporter, Nick Paumgarten, writes:

Despite the digitization of maps and the satellites circling the earth, the cartographic revolution still relies heavily on fresh observations made by people.

He goes on to describe a tour of the area near LaGuardia Airport with a pair of Navteq “field researchers” who spend their days comparing maps with reality. There are six hundred people doing this work.

But wait a sec. We’re living in the Age of Web 2.0 Participation. It’s a Two-Way Web. I know where my house is, and everyone on the east side of town knows that Hardy Ct. is a dead end. Shouldn’t there be an obvious way for millions of people to convey the ground truths they know to Navteq and Tele Atlas?