2-3 Coordinate System - Tagged.pdf

Projections and Coordinate Systems Overview Projections Examples of different projections Coordinate systems Datums Projections 2 The earth is a spheroid The best model of the earth is a globe Drawbacks: not easy to carry not good for making plan...

Projections and Coordinate Systems Overview Projections Examples of different projections Coordinate systems Datums Projections 2 The earth is a spheroid The best model of the earth is a globe Drawbacks: not easy to carry not good for making planimetric measurement (distance, area, angle) Maps are flat easy to carry good for measurement scaleable A map projection is a method for mapping spatial patterns on a curved surface (the Earth’s surface) to a flat surface. OR  an imaginary light is “projected” onto a “developable surface” a variety of different projection models exist 10 cone as developable surface secant cone tangent cone 12 plane as developable surface cylinder as developable surface tangent cylinders 15 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44