Geographic Grid - Latitudes and Longitudes

Practice flashcards covering concepts from Geographic Grid: Latitudes and Longitudes, including latitude/longitude concepts, time, GMT, IST, IDL, and great vs small circles.

What is the Geographic Grid?

A framework formed by the intersection of lines of latitude (east–west parallels) and longitude (north–south meridians) used to locate any place on Earth.

Who devised the concepts of latitude and longitude?

Eratosthenes, the Greek philosopher, who first devised lines of latitude and longitude to locate places on the Earth.

What is latitude?

The angular distance of a place north or south of the Equator; lines run east–west and are called parallels.

What is longitude?

The angular distance of a place east or west of the Prime Meridian; lines run north–south and are called meridians.

What is the Prime Meridian and why is it important?

The 0\degree longitude line that passes through Greenwich; serves as the reference for GMT and for dividing the Earth into Eastern and Western Hemispheres.

How many parallels of latitude exist at 1\degree intervals?

There are 181 parallels (from 90\degreeN to 90\degreeS, including the Equator).

What is the approximate length of 1\degree of latitude?

About 111 kilometers.

Name the major heat zones divided by latitude.

Torrid (Tropical) Zone between the Tropics of Cancer and Capricorn; Temperate Zones between the Tropics and the Polar Circles; Frigid Zones near the poles.

What is a Great Circle?

A circle on the Earth's surface whose center is the Earth's center; the Equator and all longitudes are great circles; represents the shortest path between two points.

What is a Small Circle?

Circles that do not pass through the Earth's center; all latitudinal parallels other than the Equator are small circles.

Why are great circle routes important for navigators?

They represent the shortest distance between two points on the Earth’s surface, though they may not account for weather, political, or logistical constraints.

What is GMT?

Greenwich Mean Time; the baseline mean solar time at Greenwich used to set time zones.

What is IST and how is it calculated?

Indian Standard Time; GMT + 5:30; based on the central meridian 82\degree30'E (82.5\degreeE); offset is 82.5\degree \times 4 minutes = 330 minutes = 5 hours 30 minutes.

What is the International Date Line (IDL) and its effect?

The 180\degree longitude line; crossing it changes the calendar by one day (eastward: day ahead; westward: day behind). The line zig-zags to avoid crossing national borders.

How many time zones exist on Earth and why?

24 time zones, each covering 15\degree of longitude; time within a zone is determined by its central meridian.

How is local time related to longitude?

Local time changes by 4 minutes for every degree of longitude; time increases toward the East and decreases toward the West.

How do you locate a place using latitude and longitude?

Plot the given latitude (north/south) and longitude (east/west); the intersection of the two lines marks the location.

What is the central meridian of India and its relation to IST?

82\degree30'E; this is the central meridian for IST; IST is GMT + 5:30 hours.

What is the Geographic Grid?

A framework formed by the intersection of lines of latitude (east–west parallels) and longitude (north–south meridians) used to locate any place on Earth.

Who devised the concepts of latitude and longitude?

Eratosthenes, the Greek philosopher, who first devised lines of latitude and longitude to locate places on the Earth.

What is latitude?

The angular distance of a place north or south of the Equator; lines run east–west and are called parallels.

What is longitude?

The angular distance of a place east or west of the Prime Meridian; lines run north–south and are called meridians.

What is the Prime Meridian and why is it important?

The 0\degree longitude line that passes through Greenwich; serves as the reference for GMT and for dividing the Earth into Eastern and Western Hemispheres.

How many parallels of latitude exist at 1\degree intervals?

There are 181 parallels (from 90\degreeN to 90\degreeS, including the Equator).

What is the approximate length of 1\degree of latitude?

About 111 kilometers.

Name the major heat zones divided by latitude.

Torrid (Tropical) Zone between the Tropics of Cancer and Capricorn; Temperate Zones between the Tropics and the Polar Circles; Frigid Zones near the poles.

What is a Great Circle?

A circle on the Earth's surface whose center is the Earth's center; the Equator and all longitudes are great circles; represents the shortest path between two points.

What is a Small Circle?

Circles that do not pass through the Earth's center; all latitudinal parallels other than the Equator are small circles.

Why are great circle routes important for navigators?

They represent the shortest distance between two points on the Earth’s surface, though they may not account for weather, political, or logistical constraints.

What is GMT?

Greenwich Mean Time; the baseline mean solar time at Greenwich used to set time zones.

What is IST and how is it calculated?

Indian Standard Time; GMT + 5:30; based on the central meridian 82\degree30'E (82.5\degreeE); offset is 82.5\degree \times 4 minutes = 330 minutes = 5 hours 30 minutes.

What is the International Date Line (IDL) and its effect?

The 180\degree longitude line; crossing it changes the calendar by one day (eastward: day ahead; westward: day behind). The line zig-zags to avoid crossing national borders.

How many time zones exist on Earth and why?

24 time zones, each covering 15\degree of longitude; time within a zone is determined by its central meridian.

How is local time related to longitude?

Local time changes by 4 minutes for every degree of longitude; time increases toward the East and decreases toward the West.

How do you locate a place using latitude and longitude?

Plot the given latitude (north/south) and longitude (east/west); the intersection of the two lines marks the location.

What is the central meridian of India and its relation to IST?

82\degree30'E; this is the central meridian for IST; IST is GMT + 5:30 hours.