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Direction matters

Topics/tags: Misc, technology, short

Today, I drove up to Vinton Iowa to watch a swim meet. I had mapped the path to Vinton, since it’s not a drive I make often. With a bit of prompting, Google gave me fairly straightforward directions: South on Main Street to US 6. East on US 6. North on US 63. East on US 30. North on US 218. And you’re there. Okay, those weren’t quite the directions, since there’s a bit of 218 that’s closed near the intersection of 30, but it’s close enough.

Hence, I was a bit surprised when I got in my car, turned on my phone, and was told to go North on Main to 7th, turn left, then turn right on IA 146 to head North. Why had my directions that started with US 6 East suddenly turned into directions that started with IA 146 North? The last time I checked, North and East were perpendicular to each other.

I’m stubborn, and I’d memorized the first set of direction, so I decided to head toward 6th. As soon as I turned around to head south on Main Street, Google Maps decided I should head East on US 6.

I know that Google continually optimizes, but I was stunned to discover that the direction I’m facing makes that much of a difference.

After I got home, I looked up both paths. Google wanted me to take IA 146 North to Gilman and then 390th St. East until I hit US 63. In essence, our house is at the Southwest corner of a moderately large [1] rectangle formed by IA 146 on the West, US 6 on the South, US 63 on the East, and 390th St. on the North. The speed limit on the roads is such that it doesn’t really matter which route we take to reach the Northeast corner of the rectangle, which I had to pass on the way to Vinton.

Rarely have I seen six of one, half dozen of the other so clearly exhibited by software. In this case, it shouldn’t matter to me which one I take. But there have been times that Google has decided that a gravel road is just as good as a hard surface road [2], and, well, that makes a big difference to me.

[1] About 7 miles on the short side, about 9 miles on the long side.

[2] What does the term surface road mean to you? One of my children told me it came up in a class they were in. To them, it was a shorthand for hard surface road, since they were used to the regular announcements that school buses would travel only on hard surface roads. To someone from LA, it meant the roads that are not raised. I expect that to Chicagoans, it distinguishes, say, Upper Wacker (a surface road) from Lower Wacker (a road below ground).

Version 1.0 of 2019-01-08.