Measuring and Modeling Earth: Geodetic Datums Flashcards
Geodesy
Study of the size and shape of earth
Geodetic Datum:
A model of earths size and shape which includes the origin and orientation of the coordinate systems used to map the earth.
How many radi does an elliposid have?
2
How many radi does a sphere have
1
What shape is a map projection of earth?
flat
Geoid:
Incorporates local variations in earths gravity.
What is the ellipsoid radius and what is it used for?
Equatorial and polar radii and used for GPS and long distance estimates.
Is geoid a more faithful figure of earth than Geodetic daturm?
YES!
Is a geoid an:
- ) Elliposid
- ) Sphere
- ) Irregular shape
Irregular shape!
What does geoid model have anything to do with the ocean?
Can be thought of as the surface formed if the oceans were free to fow without land and with gravity forces equal.
Is a geoid a mathematical equation?
No
In what case are projections preffered over planes?
Projections are necessary when mapping much larger portions of earths surface. Planes are fine for relatively small spaces.
What causes the shape of an elliposid?
the speed of the earth.
What causes earth to not be a spherical or elliposid shape? How is the shape governed?
Around earth gravity is different, which causes it to be a “earth like shape”
Is geodetic datum a mathematical represenatation?
A deodetic datum is a mathematical representation of the size and shape of earth.
