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CISCEISC (Arts) Class 12
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Syllabus

Overview of Study and Interpretation of Topographical Maps

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Estimated time: 24 minutes
CISCE: Class 12

Key Points: Development of Topographical Maps in India

  • Beginning – Scientific topographical mapping in India began in the 18th century. The Survey of India was established in 1767.
  • Triangulation Survey – Systematic mapping started with the Great Trigonometrical Survey under William Lambton and Sir George Everest.
  • Survey of India – Headquartered at Dehradun, it expanded mapping work across the country and produced detailed topographical maps.
  • Indian & Adjacent Countries Series – Maps drawn on 1:1,000,000 scale; each sheet covers 4° latitude and 4° longitude.
  • International Series – Based on 1:1,000,000 scale under International Map Projection; covers large parts of the world including India.
  • World Aeronautical Charts – Prepared for aviation purposes on 1:1,000,000 scale.
  • State & General Maps – After 1956, Survey of India prepared state maps (1:1 million scale) and other general maps like road, rail and tourism maps.
CISCE: Class 12

Key Points: Nomenclature and Numbering of Topographical Sheets

  • Base Series – Topographical sheets are based on the India and Adjacent Countries Series (1:1,000,000 scale). Each sheet covers 4° latitude × 4° longitude and is given an index number.
  • Quarter Inch / Degree Sheet (1:250,000) – Each 4° × 4° sheet is divided into 16 parts (1° × 1° each). These are called degree sheets.
  • Half Inch / Half Degree Sheet (1:125,000) – Each degree sheet is further divided into 4 equal parts.
  • One Inch / Quarter Degree Sheet (1:50,000) – Each degree sheet is divided into 16 smaller parts (15′ × 15′). These are called 1:50,000 topo-sheets.
  • New Series (1:25,000) – Introduced later; each 1:50,000 sheet is divided into 4 parts. These maps show greater detail and have smaller contour intervals.
CISCE: Class 12

Key Points: Conventional Signs

  • Conventional signs are symbols used on topo-sheets to represent different natural and man-made features on the ground.
  • These signs are not drawn to scale. They are only symbolic and help in giving clear and quick information.
  • Conventional signs are internationally accepted and make maps easy to read and understand.
  • Different colours are used to show land use:
    Yellow – Cultivated land
    Dark Green – Forest
    Light Green – Grassland
    Brown – Uncultivated land
    Red – Built-up areas
    Blue – Water features
    Black – Railway lines
  • The Survey of India uses standard conventional signs to represent features like roads, rivers, railways, wells, temples, boundaries, forests, etc.
CISCE: Class 12

Key Points: Interpretation of Topographical Maps

  • Introduction: Gives marginal details like sheet number, scale, year and grid reference.
  • Relief: Shown by contour lines; wide spacing = plains, close spacing = mountains.
  • Drainage: Shows rivers, lakes and drainage patterns (dendritic, radial, etc.).
  • Vegetation & Climate: Type of forests helps to guess rainfall and climate.
  • Population & Settlements: Size and pattern of settlements show population density.
  • Transport & Irrigation: Roads, railways and canals show development and farming support.
  • Occupation & Future: Land use tells main occupation; transport and industries show future growth.
CISCE: Class 12

Key Points: Study and Interpretation of Some Selected Topographical Maps

  • Scale & Area: Survey of India sheets; Hisar (plain), Mirzapur (plain + plateau).
  • Relief: Hisar – flat plain; Mirzapur – Ganga Plain & Vindhyan Plateau.
  • Drainage: Hisar – no river, canals important; Mirzapur – River Ganga main river.
  • Vegetation: Hisar – very little (semi-arid); Mirzapur – farming plain, forested plateau.
  • Settlements: Hisar – rural compact villages; Mirzapur – irregular villages, few towns.
  • Transport: Hisar – few roads, no railway; Mirzapur – roads + railway + ferry.
  • Occupation: Mainly agriculture in both areas.
CISCE: Class 12

Key Points: Means of Transport

  • Railways: Two railway lines – Northern Railway (main line) and North-East Railway (branch line).
  • Major Stations: Important stations are Mirzapur and Vindhyachal.
  • Metalled Roads: Mirzapur is the main road centre; important roads connect Lalganj, Robertsganj, Chunar, Jaunpur and Allahabad.
  • Unmetalled Roads: Kachcha roads connect smaller villages to main towns.
  • Water Transport: River Ganga is used for boat transport and has ferry crossings.
CISCE: Class 12

Key Points: Nature of Occupation

  • Agriculture: Main occupation in the fertile Ganga plain due to good irrigation.
  • Lumbering: Done in forest areas of the plateau region.
  • Cattle & Sheep Rearing: Practised in grass-covered plateau areas.
  • Quarrying: Found in five places; people work in stone quarries.
  • Industries: Some industries present, like cotton mill (Mirzapur) and carpet factory (Khamaria).
 
CISCE: Class 12

Key Points: Geographical Study and Interpretation of Topographical Sheet No.53H/3

  • Introduction: Published by Survey of India; scale 1:50,000; covers Delhi and Gurgaon districts.
  • Relief: Two regions – hilly area (200–300 m) and plain area (about 200 m); hills have steep slopes.
  • Drainage: No major river; small seasonal streams like Mehandwari Nadi; presence of tanks (Johars).
  • Vegetation & Climate: No thick forests; shrubs in hills; plains used for farming; semi-arid climate.
  • Settlements: Gurgaon is the main town; most settlements are rural and compact; hills are sparsely populated.
  • Transport & Communication: One railway line connects Gurgaon with Delhi; good network of metalled roads; post and telephone services present.
  • Irrigation & Occupation: Wells and tube-wells are main irrigation sources; agriculture is main occupation; some industries (e.g., Maruti factory).
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