1. The physical surface of the earth is called the _________.
2. The term, __________, describes gravity on the earth’s measured surface.
3. The mathematical approximation of the surface of the earth is called an _____________.
4. Geoid measurements are found via _________ ___________ (gravimeters) or from measurements of ____________ (ephemerides.)
5. The ellipsoid approximation is a required element of any ______________ system.
6. In modern geodesy, the measurement of the earth’s perameters always begins at it’s _______.
7. Name the four most important perameters of the earth: • _____________________ • _____________________ • _____________________ • _____________________
8. The oldest ellipsoid is __________ _______, which works well for only North America.
9. The two very similar ellipsoid systems that are most commonly used today are _______ _______ and _______ _______.
10. The difference between the geoid and ellipsoid height is calcuated by subtracting the ___________(h) height from the ____________(H) height (N=h-H.)
Answer Key:
1. Terrain
2. Geoid
3. Ellipsoid
4. Surface Instruments, Satellites
5. Coordinate
6. Center
7. Semi-Minor Semi-Major Flattening Eccentricity Squared
8. Clark 1866 (’66)
9. GRS 1980, WGS 1984
10. Geodetic, Orthometric
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