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The Earth Is Round - Grid Corrections

So, while looking for something else, I found this article, Mysterious Detour While Driving? This is the phenomenon, frequently observed while driving in rural America, where the road comes to a T or makes a pair of 90-degree turns for no apparent reason. I learned that some of those curves are due to the fact that the Earth is round.

When the American and Canadian plains were laid out, the goal was to survey them into equal squares of land while running the north-south boundary lines parallel to the lines of longitude. Unfortunately, these lines of longitude get closer together the closer to the pole, which in North America means going north. In order to make the squares of land equal, every so often the surveyors had to shift the squares.

This may be an explanation for something I've experienced for years. Sometimes when driving to or from the Home Soil in Central Illinois, I take a state highway, Illinois 49. There are several big paired 90-degree curves in the road, only one of which has any apparent reason for existing.

You learn something every day.

This entry was originally posted at https://chris-gerrib.dreamwidth.org/733470.html. Please comment there using OpenID.

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