The above linked article tells about surveyors locating the geographical center of San Francisco. Maybe.
In the article, it explains why it was difficult to figure out. It also doesn’t take into account the Farallon islands and Treasure Island, both of which are part of San Francisco. It also doesn’t explain why they wanted to find it, but it seems that the surveyors don’t know why, either. It’s well marked, but it may change. We will see.