![]() Blue represents water bodies and the darker the blue, the deeper the sea. Different shades of colours are used to denote differences in height e.g green represents a low land, yellow and brown represent highlands and white represents snow-capped peaks. Contour Layering: As an aid to visual impression, the space between contours are often coloured or tinted.The steeper the slope the heavier the lines which are used. Hatchures: These are short lines drawn down the slope in the direction of the steepest gradient.The height of a particular point is written on the line. The sea level is taken as the starting point in all measurements in metres or feet. Contours: These are lines drawn to join places of equal height level or altitude.They are not as accurate as contours and they are represented by broken lines. ![]() Form Lines: These are lines drawn on a map like contours but are based on estimations.They are usually represented by a triangle and a dot in the middle, with the height written by the side. ![]() Trigonometrical Stations: These are simple points on the ground marking the angle of triangulation when mapping an area.The higher the hill, the deeper the shade representing it. Hill Shading: In this method, only one colour is used but the intensity or thickness of the colour depends on the steepness of the hill.Spot Height: These are spot or points on the maps whose height above the sea level has been accurately measured.The relief of an area refers to the position and character of the highlands and lowlands in that area. +++++++++ This represents a railway line. + This sign represents hospital or dispensary. From these signs, information on the map can easily be interpreted e.g They are usually shown at the bottom of all topographical maps where the symbols are found. The map reader cannot read any map without the use of the signs. The conventional signs represent the language of the map. Enjoy the class! Representation of Relief LandformsĬonventional signs are symbols used to represent both natural and human features found in an area that is represented on a map. Spot Elevations: Marked with an“X” or are shown at many section corners, bridges, road intersections, hilltops,etc.ĭepression Contours: closed contours with hachures (short lines perpendicularto the contour line) pointing toward the lower elevations within a depression.They generally encircle small depressions.In today’s class, we will be talking about the representation of relief landforms. On a contour map, gradient is determined along a line or stream course by:ġ) using the contour lines todetermine the difference in elevation between two points Ģ) using the horizontal scale to determine the distance between thesame two points ģ) dividing the vertical difference by the horizontal distance.Įlevation or Altitude = vertical distance between that point and a fixed datum(usually mean average sea level), which by definition has an elevation ofzero.īench Mark:a point whose elevation has been precisely defined by government surveyors.Its location is marked by a small brass plate. Gradient = change in elevation overa specified horizontal distance. It is drawn as a heavy line and is labeled withits elevation. Index Contou r: as a general rule, every 5th contour, starting from sealevel, is an index contour. 6.7).Ĭontour line = line connecting all points of the same elevation.Ĭontour Interval (abbreviated as C.I.) = the difference between two consecutivecontours.ġ) the level of detail neededto be portrayed ģ) the range in elevation or relief of the area to be mapped. ![]() Elevation is added to a 2D map via contour lines(see Fig.
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