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.On a globe, the "lines" (circles) of latitude will always cross the "lines" (circles) of longitude at right angles.(A map may distort thisrelationship.)If two points are on the same meridian (constant longitude), but one degree of latitude apart, that's a distance of about 69 miles.It wouldbe the same distance, regardless of where you were, if the earth was a perfect sphere.So an error of one degree latitude corresponds to69 miles.An error of one arc-minute ('), 1.15 miles.An error of one arc-second ("), 100 feet.If two points are on the same parallel (constant latitude), but one degree of longitude apart, the distance between them would be amaximum of 69 miles (at the equator).The further away they are from the equator, the shorter the distance would be.In 1632, the down-timers did not know the true length of a degree of latitude.However, it was measured with high precision (error
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