5/6/2023 0 Comments Contour interval![]() To determine the elevation of a point on the map-Ī. The contour interval measurement given in the marginal information is the vertical distance between adjacent contour lines. Precision lightweight global positioning system receiverīefore the elevation of any point on the map can be determined, the user must know the contour interval for the map he is using. Navigation in different types of terrainĬ. It represent by V –shaped.SurvivalIQ Handbook: Land Navigation - Elevation and relief - Contour intervalsġ3. Line joining the lowest point of a valley across the contours at right is called Valley line. If the higher values are outside the loop in the contour it indicates a Valley. Line joining the highest point of a hill across the contours at right angles is called Ridge line. If the higher values are inside the loop in the contour it indicates a Ridge. For a hill reading increasing towards center, and for a pond reading decreasing towards center. Close contour loops represent either a hill or pond.Irregular contours represent rough terrain.Ridge line / Valley line intersects contour at right angle.But if contours are distant then it shows a relatively mild slope. If the contours are closely spaced then it shows steep slope.A series of closed contour line on the map represent depression, if the higher values are outside.A series of closed contour line on the map represent a hill, if the higher values are inside.If contours are parallel and equally spaced then it represents a uniform slope.In this case, several contours coincide and the horizontal equivalent become zero. Contour lines never run into one another except in the case of a vertical cliff.Contour line do not merge or intersect each other except in the cases of an overhanging cliff or cave in the hillside.A contour line is a closed curve, however they may close either on the map itself or outside the map.All the points of a contour line have the same elevation.The contour interval depends upon several factors as.Smaller contour interval is more precise for the analysis.Generally contour intervals are taken 1 to 15m.It is desirable to have a constant contour interval, however in some special cases, a variable contour may also be provided.Elevation difference between two consecutive contours is called the contour interval.To calculate the amount of cutting, filling, and reservoir capacity.In planning and designing of construction like dams, reservoirs, aqueducts, transmission lines, etc.Identifying the intervisibility of stations.In deciding where to build new industrial plants.Engineering works such as roads, canals, and other structures must be placed correctly and precisely.Note: If contours are drawn underwater they are termed as submarine contour/ Fathoms/ Bathymetric Curves. And the process of tracing contour line on the surface of the earth is called Contouring. Or It may also be defined as the intersection of level surface with the ground of the earth. Unsteady Flow: Surge- Open Channel Flow (Chapter-6)Ī contour may be defined as an imaginary line passing through points of equal elevation on the earth surface.Rapidly Varied Flow: Hydraulic Jump- Open Channel Flow (Chapter-5).Gradually Varied Flow- Open Channel Flow (Chapter-4).Energy Depth Relationship- Open Channel Flow (Chapter-3).Uniform Flow- Open Channel Flow (Chapter-2).Open Channel Flow – Introduction (Chapter-1).
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