15 PRINCIPAL CHARACTERISTICS OF CONTOUR LINE

A contour line is an imaginary line that connects points of equal height. Such lines are drawn on the plan of a region after establishing the decreasing levels of several points in a region. The contour lines of a field are drawn keeping the difference in height between two consecutive lines constant.

features of outline

The salient features of contour lines that help in plotting or reading a contour map are as follows:


  1. Contour lines should be close, not necessarily within the boundaries of the plan.
  2. The horizontal distance between any two contour lines indicates the amount of slope and is inversely proportional to the amount of slope.
  3. A widely spaced contour indicates a flat surface.
  4. Nearby contours indicate steeply sloping land.

    contour showing sloping area
    contour showing sloping area

  5. A uniformly spaced contour shows uniform slope.

    Contour showing terrain with uniform slope
    Contour showing terrain with uniform slope

  6. An irregular shape indicates an uneven surface.
  7. A nearly concentric closed figure indicates a pond with values ​​decreasing towards the center.

    Pond and its outline
    Pond and its outline

  8. Closely concentric contours indicate hills, with values ​​moving toward the center.

    hill and its outline
    hill and its outline

  9. U-shaped contour lines denote the ridge with convexity towards the lower ground.
  10. V-shaped contour lines mark the valley with convexity towards the higher ground.

    Contour showing ridge line and valley line
    Contour showing ridge line and valley line

  11. Contour lines generally do not meet or intersect. If the contour lines are meeting in a part, it indicates the existence of a vertical rock.

    steep cliff and its contour
    steep cliff and its contour

  12. Figures of different heights cannot cross each other. If the contour lines intersect, it indicates the existence of hanging rocks or a cave.

    hanging rock and its outline
    hanging rock and its outline

  13. The steepest slope of the terrain at any point on a contour is represented along the normal to the contour at that point.
  14. Contours do not pass through permanent structures such as buildings.

    contour in a permanent structure
    contour in a permanent structure

  15. A contour line should be closed on its own but not necessarily within the bounds of the map.


Er. Mukesh Kumar

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Er. Mukesh Kumar is Editor in Chief and Co-Funder at ProCivilEngineer.com Civil Engineering Website. Mukesh Kumar is a Bachelor in Civil Engineering From MIT. He has work experience in Highway Construction, Bridge Construction, Railway Steel Girder work, Under box culvert construction, Retaining wall construction. He was a lecturer in a Engineering college for more than 6 years.