Why did the united states make the gadeson purchase in 1853?

These coordinates are what the Global Position System or GPS uses to provide an accurate locational relay. Longitude and latitude lines measure the distance from the Earth's Equator or central axis - running east to west - and the Prime Meridian in Greenwich, England - running north to south.

I hope this is what you are looking for... If not I am sorry for not providing the correct/accurate answer. (^-^)