Longitude and Latitude – Notes for Competitive Examination
By Home Academy
Introduction
Latitude and Longitude are imaginary lines drawn on the Earth to determine the exact position of any place. These lines form the basis of the Geographical Coordinate System. Every location on Earth can be identified through a combination of latitude and longitude values.
Understanding latitude and longitude is extremely important for competitive examinations such as JKSSB, SSC, UPSC, JKPSC, Railways, UGC NET, and State-level examinations.
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Latitude (Parallels)
Definition
Latitude refers to the angular distance of a place north or south of the Equator measured in degrees.
Latitude lines are imaginary horizontal circles running from east to west around the Earth.
The Equator is taken as 0° latitude and acts as the reference line.
The value of latitude ranges from:
0° to 90° North (N)
0° to 90° South (S)
Characteristics of Latitude
Latitudes are parallel to each other and never meet.
They run east–west but measure distance north–south.
Equator is the longest latitude.
Length of latitude decreases toward the poles.
Latitude influences climate and temperature.
Important Latitudes of the World
| Latitude | Name | Importance |
|---|---|---|
| 0° | Equator | Divides Earth into Northern and Southern Hemisphere |
| 23½° N | Tropic of Cancer | Sun overhead on 21 June |
| 23½° S | Tropic of Capricorn | Sun overhead on 22 December |
| 66½° N | Arctic Circle | Polar day and night |
| 66½° S | Antarctic Circle | Polar day and night |
| 90° N | North Pole | Northern end of Earth |
| 90° S | South Pole | Southern end of Earth |
Example of Latitude
Delhi lies approximately at 28.6° N.
This means Delhi is located 28.6 degrees north of the Equator.
Longitude (Meridians)
Definition
Longitude refers to the angular distance of a place east or west of the Prime Meridian.
Longitude lines are imaginary vertical semicircles extending from the North Pole to the South Pole.
The Prime Meridian is taken as 0° longitude.
Longitude ranges from:
0° to 180° East (E)
0° to 180° West (W)
Characteristics of Longitude
Longitudes meet at both poles.
They run north–south but measure east–west distance.
Prime Meridian passes through Greenwich, England.
Longitudes help determine time zones.
All longitudes are equal in length.
Important Longitudes
| Longitude | Importance |
|---|---|
| 0° | Prime Meridian |
| 180° | International Date Line (approximately) |
| 82°30′ E | Standard Meridian of India |
Example of Longitude
New Delhi lies approximately at 77.2° E.
This means New Delhi is located east of the Prime Meridian.
How Latitude and Longitude Work Together
A location is identified using both values.
Example:
New Delhi → 28.6° N, 77.2° E
Interpretation:
28.6° north of Equator and 77.2° east of Prime Meridian.
Difference Between Latitude and Longitude
| Basis | Latitude | Longitude |
|---|---|---|
| Definition | Distance north or south of Equator | Distance east or west of Prime Meridian |
| Direction | East–West | North–South |
| Range | 0°–90° | 0°–180° |
| Reference Line | Equator | Prime Meridian |
| Shape | Complete circles | Semi-circles |
| Length | Unequal | Equal |
| Main Use | Climate | Time calculation |
Standard Time and Longitude
Earth rotates 360° in 24 hours
Therefore:
360° ÷ 24 = 15° per hour
1° longitude = 4 minutes
India uses 82°30′ E longitude as Indian Standard Time (IST).
IST passes near Mirzapur, Uttar Pradesh.
Latitude and Climate Relation
Places near Equator receive direct sunlight and are hotter.
Places near poles receive slanting rays and remain colder.
Example:
Singapore → Hot climate (near Equator)
Greenland → Cold climate (near poles)
International Date Line (IDL)
The International Date Line lies approximately at 180° longitude.
Crossing IDL:
Westward → Add one day
Eastward → Subtract one dayIt bends to avoid dividing countries and islands.
Important Examination Facts
Equator divides Earth into two hemispheres.
Prime Meridian divides Earth into Eastern and Western Hemisphere.
Latitude determines climate.
Longitude determines local time.
Earth rotates from west to east.
No latitude is a great circle except Equator.
All meridians are equal in length.
Tropic of Cancer passes through India.
Standard Meridian of India is 82°30′ E.
Arctic and Antarctic Circles lie at 66½°.
MCQ Questions (Single Correct Answer)
Q1. What is the value of the Equator?
A. 90°
B. 66½°
C. 0°
D. 23½°
Answer: C
Q2. Prime Meridian passes through:
A. Paris
B. Greenwich
C. Tokyo
D. Rome
Answer: B
Q3. Indian Standard Time is based on:
A. 70° E
B. 82°30′ E
C. 90° E
D. 60° E
Answer: B
Q4. Which latitude receives vertical sun rays on 21 June?
A. Tropic of Capricorn
B. Equator
C. Tropic of Cancer
D. Arctic Circle
Answer: C
Q5. Longitudes are useful in determining:
A. Climate
B. Rainfall
C. Time
D. Soil
Answer: C
Q6. International Date Line is approximately located at:
A. 0°
B. 90°
C. 180°
D. 360°
Answer: C
Statement Type Questions (More Than One Option Correct)
Q1. Consider the following statements regarding Latitude:
Equator is 0° latitude.
Latitudes meet at poles.
Latitude affects climate.
Tropic of Cancer lies at 23½° N.
Options:
A. 1 and 2 only
B. 1, 3 and 4 only
C. 2 and 4 only
D. All are correct
Answer: B
Q2. Consider the following statements regarding Longitude:
Prime Meridian is 0°.
Longitudes determine local time.
Longitudes are equal in length.
Longitudes never meet.
Options:
A. 1 and 2 only
B. 1, 2 and 3 only
C. 2 and 4 only
D. All are correct
Answer: B
Q3. Which of the following statements are correct?
Earth rotates 15° in one hour.
India follows 82°30′ E longitude.
Equator is the longest latitude.
Latitude determines time.
Options:
A. 1, 2 and 3 only
B. 2 and 4 only
C. 1 and 4 only
D. All are correct
Answer: A
Quick Revision Formula
Latitude → Climate → Equator → North–South Position
Longitude → Time → Prime Meridian → East–West Position
Total Number of Lines of Latitude (Parallels)
Lines of latitude run horizontally, parallel to the Equator. They are measured from 0° circ at the Equator up to 90° circ North and 90° circ South.
- North of the Equator: 90 lines (1°N to 90° N)
- South of the Equator: 90 lines (1°S to 90°S)
- The Equator: 1 line 0°
- Total Latitudes = 90 + 90 + 1 = 181
The North Pole (90°)and South Pole (90°) are technically points rather than full circular lines, but they are still counted as lines of latitude in standard geographic totals. If you exclude the two poles, there are 179 lines.
Total Number of Lines of Longitude (Meridians)
Lines of longitude run vertically from the North Pole to the South Pole. They are measured from 0^\circ at the Prime Meridian up to 180^\circ East and West.
- East of the Prime Meridian: 179 lines (1° to 179°
- West of the Prime Meridian: 179 lines (1° to 179°
- The Prime Meridian: 1 line 0°
- The Anti-Meridian: 1 line 180°
Here is the complete list of countries that the Tropic of Cancer, Tropic of Capricorn, Equator, and Prime Meridian pass through.
1. Countries on the Tropic of Cancer (23.5°circ)
The Tropic of Cancer passes through 16 countries across three continents, as well as one self-governing territory (Taiwan).
- North America: Bahamas, Mexico
- Africa: Egypt, Libya, Niger, Algeria, Mali, Mauritania, Western Sahara (territory)
- Asia: Taiwan, China, Myanmar (Burma), Bangladesh, India, Oman, United Arab Emirates (UAE), Saudi Arabia
2. Countries on the Tropic of Capricorn (23.5° circ)
The Tropic of Capricorn passes through 10 countries across three continents.
- South America: Brazil, Paraguay, Argentina, Chile
- Africa: Mozambique, South Africa, Botswana, Namibia, Madagascar
- Oceania: Australia
3. Countries on the Equator (0° circ Latitude)
The Equator passes through the land or territorial waters of 13 countries across three continents.
- South America: Ecuador, Colombia, Brazil
- Africa: Sao Tome and Principe, Gabon, Republic of the Congo, Democratic Republic of the Congo (DRC), Uganda, Kenya, Somalia
- Asia/Oceania: Maldives*, Indonesia, Kiribati*
*Note: The Equator passes through the territorial waters/exclusive economic zones of the Maldives and Kiribati, but the line does not physically cut across their landmasses.
4. Countries on the Prime Meridian (0° circ Longitude)
The Prime Meridian passes through 8 countries across two continents (Europe and Africa), as well as Antarctica.
- Europe: United Kingdom, France, Spain
- Africa: Algeria, Mali, Burkina Faso, Togo, Ghana
- Antarctica: Queen Maud Land (claimed territory)
Quick Reference Summary Table
|
Line of Measurement |
Total Countries/Territories |
Main Continents Crossed |
|---|---|---|
|
Tropic of Cancer |
17 |
North America, Africa, Asia |
|
Tropic of Capricorn |
10 |
South America, Africa, Oceania |
|
Equator |
13 |
South America, Africa, Asia |
|
Prime Meridian |
8 |
Europe, Africa |
The word Greenwich (pronounced GREN-itch) is one of the most famous names in geography and timekeeping.
Here is everything you need to know about Greenwich and its massive global significance:
1. The Home of the Prime Meridian (0° circ Longitude)
Greenwich is a historic borough in London, England. In 1884, an international conference chose the Royal Observatory in Greenwich as the official location for the Prime Meridian.
- The exact line of 0^°circ longitude runs right through the courtyard of the observatory.
- It serves as the baseline that divides the Earth into the Eastern Hemisphere and the Western Hemisphere.
- When you stand on the physical line in Greenwich, you can literally have one foot in the eastern half of the world and one foot in the western half.
2. Greenwich Mean Time (GMT)
Because the Prime Meridian is located here, Greenwich became the center for world timekeeping.
- Greenwich Mean Time (GMT) was originally the standard solar time measured at the Royal Observatory.
- Historically, sailors used GMT to calculate their longitude at sea, helping them navigate the globe safely.
- Today, while the world officially uses UTC (Coordinated Universal Time) for high-precision technology, GMT is still widely used as a time zone reference for the United Kingdom, parts of Africa, and Western Europe during the winter.
3. Why Greenwich?
Before 1884, different countries used their own "prime meridians" (Paris, Washington D.C., and Rio de Janeiro were all used). Greenwich was chosen as the single global standard for two main reasons:
- Existing Maritime Charts: At the time, over 70% of the world's shipping commerce already used sea charts based on the Greenwich Meridian.
- Convenience for the Date Line: Placing the 0^\circ line at Greenwich meant that the International Date Line (180° circ) would fall directly over the Pacific Ocean, minimizing confusion by ensuring it passed through very little inhabited land.