Measuring and Modeling Earth: Geodetic Datums Flashcards Preview

Geography 222 Midterm > Measuring and Modeling Earth: Geodetic Datums > Flashcards

Flashcards in Measuring and Modeling Earth: Geodetic Datums Deck (17)
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1
Q

Geodesy

A

Study of the size and shape of earth

2
Q

Geodetic Datum:

A

A model of earths size and shape which includes the origin and orientation of the coordinate systems used to map the earth.

3
Q

How many radi does an elliposid have?

A

2

4
Q

How many radi does a sphere have

A

1

5
Q

What shape is a map projection of earth?

A

flat

6
Q

Geoid:

A

Incorporates local variations in earths gravity.

7
Q

What is the ellipsoid radius and what is it used for?

A

Equatorial and polar radii and used for GPS and long distance estimates.

8
Q

Is geoid a more faithful figure of earth than Geodetic daturm?

A

YES!

9
Q

Is a geoid an:

  1. ) Elliposid
  2. ) Sphere
  3. ) Irregular shape
A

Irregular shape!

10
Q

What does geoid model have anything to do with the ocean?

A

Can be thought of as the surface formed if the oceans were free to fow without land and with gravity forces equal.

11
Q

Is a geoid a mathematical equation?

A

No

12
Q

In what case are projections preffered over planes?

A

Projections are necessary when mapping much larger portions of earths surface. Planes are fine for relatively small spaces.

13
Q

What causes the shape of an elliposid?

A

the speed of the earth.

14
Q

What causes earth to not be a spherical or elliposid shape? How is the shape governed?

A

Around earth gravity is different, which causes it to be a “earth like shape”

15
Q

Is geodetic datum a mathematical represenatation?

A

A deodetic datum is a mathematical representation of the size and shape of earth.

16
Q

What is a projection that is an example of a geodetic datum?

A

Lambert Conformal Conic secant! (2 standard lines (somewhere between equator and poles)

17
Q

Is a grid or a graticule on a datum?

A

A graticule is on a datum and a grid is what is on a 2-D surface!