This film was made mining the Thomas Jefferson’s Grid in Google Earth. By superimposing a rectangular grid on the earth surface, a grid built from exact square miles, the spherical deviations have to be fixed. After all, the grid has only two dimensions.
The north-south boundaries in the grid are on the lines of longitude, which converge to the north. The roads that follow these boundaries must dogleg every twenty-four miles to counter the diminishing distances: Grid Corrections
Read more on BLDGBLOG: http://www.bldgblog.com/2015/12/grid-corrections/