Geographical representation

• Contour lines

  Imaginary lines joining places which have the same height above the sea level
• Contour lines on topographical maps

  • Shown with brown lines
  • Never intersect each other
  • Each contour line has its own numerical value
  • Difference in height between two adjacent contour lines is called the contour interval
  • Every fifth contour line is drawn bold and is known as the contour index
• Topography

  Indicates Relief features such as mountains, hills, ridges, valleys and coastal plains
• Topographical maps


  • Combine natural features and human-made features on a single sheet with the help of colours and conventional symbols
  • Produced by the Survey of India
  • An important tool for geographers to make in-depth study of a region
• Use of contours on topographical sheets

  • Show height of the land
  • Show steepness of the slope
  • Show shape of the land
• Steep slope


  • Closely spaced contour lines
• Gentle slope


  • Widely spaced contour lines
• Hill


  • Large mass of land that rises to a height, much above the surrounding area
  • Conical hill with uniform slope on all sides has contour lines drawn in a concentric manner, evenly spaced with value increasing towards the centre
• Plateau


  • Large mass of comparatively flat land that rises abruptly from the surrounding area
  • Surface is undulating and it usually has steep slopes on one or more sides
  • Contour lines are drawn in an elongated manner, with the value increasing on the inner side, close together on the steep side and widely spaced on the gentle side
• Ridge


  • Narrow, elongated hill with steep slopes
  • Represented on the map by elliptical contours that are closely spaced
  • Top is not flat and usually has a number of small summits separated by depressions
• Col

  Narrow and steep-sided depression on the top of a ridge
• Saddle

  Broad and low depression that gently descends from the summit of a ridge
• Pass

  Narrow gap in a range of mountain that provides a passage through it
• Gap

  Pass that has been lowered in height by the action of river
• Dispersed settlements

  • Scattered houses in hilly, forested areas and deserts where accessibility is poor
• Nucleated or compact settlements

  • Houses built close together in river valleys and fertile plains where land is flat and accessibility is good
• Linear settlements


  • Houses built in a line, usually facing each other, along river banks, coasts, roads or railway lines
• Temporary settlements are where nomadic people stay for a short period of time
• Most settlements are permanent, where people live for long period of time
• Interpretation of topographical sheet

  • Identifying and describing the physical and human-made features and their inter-relationship
• The region has two distinct physical divisions: a hilly area in the south-east and east, and a large plain land in the remaining portion
• The hilly area presents a rugged topography with steep slopes and heights over 400 m, and several ridges with cols and saddles
• The plain land is traversed by the Sipu River and its tributaries, with a general slope towards the west
• The hilly area is forested with dry deciduous type of forests, while the plain land has agricultural areas and wastelands dotted with isolated trees
• The plain land has several nucleated settlements with important civic facilities, while the hilly area is devoid of any settlements
• The main occupation in the plain land is agriculture, while people in the hilly area are engaged in collection of forest products and small-scale lumbering
• NH 168 passes through the region, connecting the major settlements, with other metalled roads and cart tracks connecting smaller settlements
• Triangulated Height


  A point that has been accurately surveyed, shown with a triangle
• Spot Height


  Height of a point on the ground above the mean sea level, shown with a dot
• Bench Mark


  Mark etched on a stone or a building to indicate the accurate height determined by survey
• Relative Height


  Difference between maximum and minimum height of a place, represented by the letter 'r'