Great circles (23-05-18)

Question 1

What is a great circle?

Answer 1

a circle around the earth with radius and centre matching that of the Earth.

Question 2

What is a small circle?

Answer 2

Any circle that is not a great circle.

Question 3

How many great circle options do antipodal points have?

Answer 3

infinite

Question 4

What is a loxoddrome/loxodromic line?

Answer 4

A rhumb line from the equator to a pole, which causes a spiral track.

Question 5

What is a rhumb line?

Answer 5

A line connecting 2 positions that crosses all meridians at the same angle relative to north.

Question 6

When comparing rhumb lines and great circles, which is always closer to the nearest pole?

Answer 6

A great circle.

Question 7

When do great circles and rhumb lines intersect?

Answer 7

At the equator.

Question 8

What is geocentric latitude?

Answer 8

latitude measured at the centre of the earth from the equator.

Question 9

What is geodetic/geographic latitude?

Answer 9

latitude measure at a point off set from the centre of the earth which intersects the earths surface at 90degrees, due to the elliptic profile of the Earth.

Question 10

Where is the maximum difference between geodetic and geocentric latitudes found, and what is the maximum difference?

Answer 10

it is found at 45degN/S and the difference is 11.6’ of arc.

Question 11

At what latitude is the arctic circle found?

Answer 11

66.5degN

Question 12

At what latitude is the Tropic of Cancer found?

Answer 12

23.5degN

Question 13

At what latitude is the equator found?

Answer 13

00degN/S

Question 14

At what latitude is the Tropic of Capricorn found?

Answer 14

23.5degS

Question 15

At what latitude is the Antarctic circle found?

Answer 15

66.5degS

Question 16

What is a change in lat referred to as?

Answer 16

Chlat.

Question 17

Where is the prime meridian found?

Answer 17

000degE/W

Question 18

In terms of longitude, what makes up a great circle?

Answer 18

a meridian and its corresponding antimeridian.

Question 19

What is the change in longitude referred to as?

Answer 19

Chlong

Question 20

What is the intersection between lines of latitude and longitude called?

Answer 20

A graticule

It is always a 90 degrees intersection

Question 21

What 3 conditions are required in order to do basic distance calculations based on positions via longitude/latitude?

Answer 21

1- The positions on different latitudes bu the same longitude

2- the positions are on the equator on different longitudes

3 - the positions are on the same latitude and on meridians that are opposite each other (Polar transit)