Intro to Geodesy (Pres II)

Question 1

What is Geodesy?

Answer 1

Measurement & representation of the Earth & other planetary bodies, including their gravity fields, in a 3D, time varying space.

Question 2

What MUST we consider in Geodesy?

Answer 2

Curvature of Earth

Gravity

Question 3

What is Geomatics?

Answer 3

Gathering, storing, processing, & delivering georeferenced information

Question 4

What are the 3 sections is Geodesy divided into?

Answer 4

Global Geodesy
Geodetic Surveying
Plane Surveying

Question 5

What does global geodesy encompass?

Answer 5

The entire earth

Question 6

What does geodetic surveying encompass?

Answer 6

A continent or smaller portion of land that still has to consider curvature and gravity
NGS, NIGA (National Intelligence Geospatial Agency)

Question 7

What does plane surveying encompass?

Answer 7

Smaller scale that does not need to consider curvature or gravity

Question 8

What is the problem of geodesy?

Answer 8

Determine the figure & gravity field of Earth & other celestial bodies as a function of time, from observations on the surface

Question 9

What is the Geoid?

Answer 9

The exact surface of the Earth. Cannot be defined mathematically

Question 10

What do we consider the Earth for our purposes?

Answer 10

Ellipsoid

Question 11

Pythagoras ~400BC

Answer 11

First to believe in spherical Earth

Question 12

Erastosthenes ~200BC

Answer 12

Founder of Geodesy
Determined radius of the Earth within a 7% error
Used the sun’s shadow in wells in Alexandria and Syrene to make this calculation

Question 13

Hipparchus ~150BC

Answer 13

Catalogued 71,000 stars in RA coordinate system
Discovered precession of equinoxes
Did not believe heliocentric theory

Question 14

Mercator ~1500AD

Answer 14

Father of modern cartography

Question 15

Copernicus ~1530AD

Answer 15

Heliocentric Theory

Question 16

Kepler ~1650AD

Answer 16

Laws of planetary motion

Question 17

Snell ~1700AD

Answer 17

Refraction, triangulation, radius of Earth

Question 18

Newton ~1700AD

Answer 18

Theory of gravitation

Predicted Earth should be oblate spheroid

Question 19

Gauss ~1750AD

Answer 19

Great mathematician
Invented bell curve and normal distribution
Defined Geoid
Invented LEAST SQUARES

Question 20

Darwin ~1900

Answer 20

Theory of Earth’s tides

Question 21

Einstein ~1950

Answer 21

Theory of relativity

clocks go faster on satellites because of less gravity

Question 22

Tuzo Wilson ~modern era

Answer 22

Founded Plate Tectonics theory, including hotspots

Question 23

Sir Sanford Fleming ~modern era

Answer 23

Father of standard time
Time changes 4 minutes from meridian to meridian
24 time zones and each is 15 degrees

Question 24

What have modern developments in geodesy relied heavily upon?

Answer 24

Introduction of new techniques & instrumentations starting in the WWII era:
Radar
Computers
EMD
Satellites (1st was Russia, Oct 4, 1967, Sputnik)
VLBI
Lasers (terrestrial, SLR, LLR)
Microelectronics

Question 25

Name 3 international geodesy organizations

Answer 25

IUGG (international Union of Geodesy & Geophysics)
IAG (international Association of Geodesy)
FIG (international Federation of Surveyors)