Coordinate Systems in Geography

Study Notes

Coordinate Systems

A geographic grid coordinate system is a method of assigning a unique set of coordinates to every location on the Earth's surface.
There are several types of coordinate systems, including:
- Geographic Coordinate System (GCS): based on latitude and longitude
- Universal Transverse Mercator (UTM) System: a 2D Cartesian system that divides the Earth into 60 zones
- State Plane Coordinate System (SPCS): a 2D Cartesian system used in the United States

Latitudes

Latitude is an angular distance measured from the Equator, ranging from 0° to 90° (North or South).
Latitude is divided into:
- Equator (0°): the middle point between the North and South Poles
- Tropic of Cancer (23.5° N): the northernmost point on Earth where the Sun can be directly overhead
- Tropic of Capricorn (23.5° S): the southernmost point on Earth where the Sun can be directly overhead
- Arctic Circle (66.5° N): the northernmost point on Earth where the Sun can be seen at midnight on the summer solstice
- Antarctic Circle (66.5° S): the southernmost point on Earth where the Sun can be seen at midnight on the summer solstice

Longitudes

Longitude is an angular distance measured from the Prime Meridian, ranging from 0° to 180° (East or West).
Longitude is divided into:
- Prime Meridian (0°): passes through Greenwich, England, and is the reference point for measuring longitude
- International Date Line (180°): separates two consecutive calendar days
- East longitude (0° to 180°): measured east of the Prime Meridian
- West longitude (0° to 180°): measured west of the Prime Meridian

Coordinate Systems

A geographic grid coordinate system assigns a unique set of coordinates to every location on the Earth's surface.
There are multiple types of coordinate systems, including:
- Geographic Coordinate System (GCS) based on latitude and longitude.
- Universal Transverse Mercator (UTM) System, a 2D Cartesian system dividing the Earth into 60 zones.
- State Plane Coordinate System (SPCS), a 2D Cartesian system used in the United States.

Latitudes

Latitude is an angular distance measured from the Equator, ranging from 0° to 90° (North or South).
The Equator is 0° latitude, the middle point between the North and South Poles.
The Tropic of Cancer is 23.5° N, the northernmost point on Earth where the Sun can be directly overhead.
The Tropic of Capricorn is 23.5° S, the southernmost point on Earth where the Sun can be directly overhead.
The Arctic Circle is 66.5° N, the northernmost point on Earth where the Sun can be seen at midnight on the summer solstice.
The Antarctic Circle is 66.5° S, the southernmost point on Earth where the Sun can be seen at midnight on the summer solstice.

Longitudes

Longitude is an angular distance measured from the Prime Meridian, ranging from 0° to 180° (East or West).
The Prime Meridian is 0° longitude, passing through Greenwich, England, and is the reference point for measuring longitude.
The International Date Line is 180° longitude, separating two consecutive calendar days.
East longitude ranges from 0° to 180°, measured east of the Prime Meridian.
West longitude ranges from 0° to 180°, measured west of the Prime Meridian.

Geographic Grid Coordinates

Latitudes

Imaginary lines that run parallel to the equator, measuring distance north or south of the equator.
Range from 0° to 90° north (N) or south (S) of the equator.
Typically marked in increments of 1°, with finer divisions of 1' (minute) and 1" (second).
Parallel to each other and to the equator.
Equidistant from each other (approximately 111 km or 69 miles apart).
Increase in value as you move towards the poles.

Longitudes

Imaginary lines that run from the North Pole to the South Pole, measuring distance east or west of the prime meridian.
Range from 0° to 180° east (E) or west (W) of the prime meridian.
Typically marked in increments of 1°, with finer divisions of 1' (minute) and 1" (second).
Converge at the poles and are widest at the equator.
Not parallel to each other, but intersect at the poles.
Increase in value as you move east or west from the prime meridian.

Key Points

The intersection of a latitude and longitude line creates a unique geographic coordinate.
Latitude and longitude values can be expressed in degrees, minutes, and seconds (e.g., 43° 12' 30" N, 122° 45' 20" W).
The combination of latitude and longitude allows for precise location identification on the Earth's surface.

Description

Learn about different types of coordinate systems used to locate points on the Earth's surface, including Geographic Coordinate System, Universal Transverse Mercator System, and State Plane Coordinate System.