In recent days, because apparently they don't have enough to do, the city's Department of Public Works installed a small brass disc marker on a sidewalk on Corbett Avenue, the 700 block, on the slope of Twin Peaks, one block off of Upper Market. It marks the geographic center of the city, they say, give or take 30 feet, and not counting several other factors. The Chronicle cheekily inquires why this was important to know, and DPW director Mohammed Nuru isn't exactly sure, he just knows it is.

When a reporter pointed out that it was kind of convenient that the geographic center didn't fall on private property or in the middle of some bushes, head surveyor Bruce Storrs apparently lowered his voice and pointed some bushes about 30 feet away and said, "That's the actual spot." But, anyway, close enough!

Surveyors used satellites and sophisticated instruments to determine the actual center, which actually varies by a number of yards depending on whether it's low or high tide, and this is not counting Treasure Island, which is technically part of San Francisco.

Soon, DPW says, they'll be replacing the little brass disc with a more significant plaque, perhaps hoping this will be a tourist attraction?

Department spokesperson Rachel Gordon tells NBC Bay Area, "We just wanted to know where it was," adding that it didn't take up a lot of resources and the surveying team "just had to do the magic work on the computers to come up with the number."

This actually isn't the first time someone has installed a monument at a not precisely accurate geographic center of town. Adolph Sutro installed a grand statue and pediment vaguely nearby at what's now Upper Terrace in 1887, which you can see photos of here, that ultimately crumbled and fell into disrepair. Only the pediment now remains, tucked among some trees.

Related: SFMTA Approves Controversial Twin Peaks Car Ban