Notes on Fundamentals of Geography

Introduction to Latitudes

• Definition: Imaginary horizontal lines on Earth.
• Creation:
  • Geographers first drew a line connecting the North and South Pole.
  • A horizontal line was drawn at the midpoint called the Equator (0 degrees).

Understanding Latitude

• Latitude is defined as the angular distance from the Equator.
• Latitude is expressed in degrees:
  • Example: 15° Latitude, 45° Latitude, 90° Latitude (Pole).
• Concentric Circles: All latitudes are concentric circles centered on the Earth's axis.
• Parallels: All latitudes are parallel and never touch each other.

Prominent Latitudes

• Equator (0°): Reference line.
• Tropics: 23.5° North (Tropic of Cancer) and 23.5° South (Tropic of Capricorn).
• Arctic and Antarctic Circles: 66.5° North and 66.5° South.

Zones of Latitude

• Tropical Zone: Between the two tropics.
• Temperate Zone: Between the tropics and the Arctic Circle.
• Polar Zone: Beyond the Arctic Circle.

Heat Distribution

• Heat Surplus: Tropical Zone.
• Heat Deficit: Temperate and Polar Zones.
• Sunlight Reception: Earth’s spherical shape causes uneven heating - direct at the equator and more dispersed at poles.

Earth's Tilt and Seasons

• Earth is tilted at 23.5 degrees.
• This tilt leads to varying seasons:
  • When the Northern Pole is tilted towards the Sun, it is summer in the Northern Hemisphere.
  • Opposite occurs in the Southern Hemisphere.
• Seasons: Result of Earth's tilt and revolution around the Sun.

Earth's Revolution and Solstices

• Elliptical Path: Causes varying distances from the Sun.
• Solstices:
  • Summer Solstice: Longest day in Northern Hemisphere (June).
  • Winter Solstice: Longest day in Southern Hemisphere (December).
• Equinoxes:
  • Equal day and night; occurs in Spring (March) and Autumn (September).

Daylight Variation

• Day length variation is more pronounced in temperate regions than tropical regions.
• Daylight Saving Time: Adjustments made in temperate regions to optimize daylight use in summer.

Longitudes

• Definition: Vertical lines running from Pole to Pole.
• Prime Meridian: Established at Greenwich (0° Longitude).
• International Date Line: 180° longitudinal line opposite the Prime Meridian.

Managing Dates and Times

• Zigzag Pattern: International Date Line ensures no land divides dates to avoid confusion.
• Time Calculation:
  • Earth rotates 15° per hour.
  • Time differences are calculated based on degrees from Greenwich.
• Example: India’s Standard Time (IST) at 82.5° E results in a time difference of +5.5 hours from GMT.

Special Cases: Chai Bagan Time Zone

• Historical time zone created for tea planters in Northeast India.
• Current discussions on reinstating a separate time zone.

Map Exercises

• Practice Questions: Identify countries and cities near the equator and prime meridian.
• Understand the geographical significance of various straits and trade routes, such as the Strait of Malacca and Gibraltar.

Conclusion

• Importance of understanding latitudes and longitudes for geography.
• Recommended to study NCERT geography books for foundational knowledge.