CONS 127 Study Guide - Spring 2018, Comprehensive Midterm Notes -
12 Oct 2018
School
Department
Course
Professor
CONS 127
MIDTERM EXAM
STUDY GUIDE
Fall 2018
CONS 127
Jan 9 2018
Observing Your Position on the Earth
Origin of Latitude and Longitude
Before 1482, all maps had no coordinates. The blue and orange map from 1482 by Ptolemy shown in
lecture slide is special because it was the first map with coordinates→ First map ever with grid
system.
However, this map was completely and totally wrong.
Terms Definition:
Latitude: these are the horizontal lines. Lines going from left to right/side to side
Longitude: these are the vertical lines. Lines that cut down from top to bottom
Some Terms Definition:
Equator: cuts right across the centre of earth-->0° Latitude
Arctic circle: the highest you can go when the sun never sets (in summer) or where the sun never rises
(in winter)
Tropic of Cancer, and Tropic of Capricorn: they are both latitudes. Here, the sun is directly overhead
Terms Under Latitude
Latitude: angle that describes the north-south position. Latitudes go straight across lines i.e. horizontal
lines. i.e. Equator is a latitude (it cuts right across from left to side)
Parallel: these are the lines that go horizontally. *The Longitude version of this is meridian
Lines of latitude= called "parallels"
Pole: Axis of rotation
Equator: This is the biggest parallel. Why? → it has the widest girth because it is around the widest
part of the Earth
Arctic Circle: Imaginary circle above the equator. Known as the place where the sun never sets in
the summer
Antarctic Circle: Imaginary circle below the equator.
Tropic of Cancer: Above the equator. Where the sun is directly overhead
Tropic of Capricorn: Below the equator. Where the sun is directly overhead
Important Notes to Remember:
0° LATITUDE is the EQUATOR-->>Anything north of the equator increases in degrees. Increases
from 0° (equator) - 90° (North Pole).
Earth's Axial Tilt
The Earth is rotated like a top→it's tilted.
It doesn't rotate directly north or south, so it’s not perfectly rotating as Earth is leaning slightly
As a result of tilt→we get seasons
find more resources at oneclass.com
find more resources at oneclass.com
Seasons: happens when parts of the Earth is rotating away from the sun/parts of the earth is rotating
closer to the sun.
Terms Under Longitude
What is Longitude?
Longitude is slicing the apple straight down. Up and down
Longitude: east-west position
Meridian: These are the lines of the longitude. *The Latitude version is parallels
Lines of longitude= called "meridians"
Prime Meridian: This passes through in Greenwich, this is the ZERO degrees longitude mark.
Some Terms Definition:
0° Longitude → Passes right through Greenwich (city in UK)
Defining Position with Latitude and Longitude
This is the coordinate system (usage of latitude and longitude) that tells you where we are on the
Earth's surface
Longitude: 0°-180°
Latitude: 0°-90°
The Shape of the Earth
Sphere: We assume it's a perfect circle... However, Earth IS NOT a perfect circle
What does geodesy mean? Just the science and mathematics dealing with the shape and area of the
Earth
We have terms to describe the Earth in regards of shape:
Oldest to More Recent Definition of the Shape of the Earth
1. Sphere: this is where we assume that the Earth is perfectly round and that the radius of the Earth is
the same all the way around (constant) a=b. THIS IS WRONG.
2. Ellipsoid: this is the definition where the Earth is a big squashed i.e. Wider at the sides, but
squashed from the head and bottom. a ≠ b. Fatter at sides than at the top. STILL A WRONG
DEFINITION BUT A BIT CLOSER TO THE TRUE DEFINITION.
3. Geoid: It's a lumpy Earth… It’s not very pretty. Because the Earth has waves and tides, it's difficult
to find what the Earth truly looks like naked. Geoid is the BEST description to describe the Earth. An
ugly, lumpy... shape.. THIS IS THE MODEL WE USE.
Google Maps
find more resources at oneclass.com
find more resources at oneclass.com
