![]() Line 1 starts with the contour interval, not the projection point. Slope Worksheet - Use the information from the example above and complete the slope worksheet. The run is 1000 feet and the rise in elevation is 120 feet. Step 4. Use the slope percent equation and solve. Set up the cancellation table so all units will cancel, except the desired unit, feet. Step 2. Use the appropriate conversion factor to convert the horizontal map distance to horizontal ground distance. The horizontal map distance measures 0.5 inches. Step 1. Measure the horizontal map distance between points A and B to get the vertical ground distance. The horizontal distance between points A and B can be measured with a scaled ruler and used to determine the slope percent.Įxample 4 - What is the slope percent in Exercise 2 above?įor this computation, the rise, or vertical ground distance, and run, or horizontal ground distance, are needed. Notice the tick marks pointing toward lower elevation. The figure above illustrates a depression and its representation using contour lines. (b) Notice how a mountain saddle, a ridge, a stream, a steep area, and a flat area are shown with contour lines. The figure above illustrates various topographic features. Contour lines that are very close together indicate a steep slope. Widely separated contour lines indicate a gentle slope. The peak is normally considered to be located at half the interval distance. Note: The intervals are increasing, therefore, the contours indicate a hill. ![]() From the contour map, a profile can be drawn of the terrain.Įxample 2 - Draw a profile showing the elevations of the contours. The even spacing indicates the hill has a uniform slope. The contour lines in this figure are equally spaced. Pick two contour lines that are next to each other and find the difference in associated numbers. Sharp contour points indicate pointed ridges.Įxample 1 - In the graphic below, what is the vertical distance between the contour lines? Contour lines tend to enclose the smallest areas on ridge tops, which are often narrow or very limited in spatial extent. ![]() A rounded contour indicates a flatter or wider drainage or spur. They then cross the stream and turn back along the opposite bank of the stream forming a "v". As a contour approaches a stream, canyon, or drainage area, the contour lines turn upstream. If the numbers associated with the contour lines are decreasing, there is a decrease in elevation. If the numbers associated with specific contour lines are increasing, the elevation of the terrain is also increasing. Index contours are bold or thicker lines that appear at every fifth contour line. A contour interval is the vertical distance or difference in elevation between contour lines. The definition of this map symbol was updated on : Change of the text: Contour lines shall be adapted or, if not possible, cut in order not to touch symbols Small knoll (109) or Small elongated knoll (110).A contour line is a line drawn on a topographic map to indicate ground elevation or depression. The definition of this map symbol was updated on : Adding Stairway (532) as a symbol, where contour lines shall be cut out for better legibility. The smallest bend in a contour is 0.4 mm from This deviation should not exceed 25% of the contour interval and attention must be paid to neighbouring features. ![]() ![]() It is permissible to alter the height of a contour slightly if this will improve the representation of a feature. Absolute height accuracy is of less importance. The relative height difference between neighbouring features must be represented on the map as accurately as possible. Contour lines shall be adapted or, if not possible, cut in order not to touch symbols Small knoll (109) or Small elongated knoll (110). A contour interval is the vertical distance or difference in elevation between contour lines. However, contour lines shall be cut out for better legibility, if they touch the following symbols: Small earth wall (105), Small depression (111), Pit or hole (112), Prominent landform feature (115), Stairway (532). When used, they should be placed in re-entrants. Slope lines may be drawn on the lower side of a contour line to clarify the direction of slope. To emphasize the 3-dimensional effect of the contour line image, contour lines shall be represented as continuous lines through all symbols, also Building (521) and Canopy (522). The standard vertical interval between contours is 2 or 2.5 m. 714 Temporary construction or closed areaĪ line joining points of equal height.526 Cairn, memorial, small monument or boundary stone.501.2 Step or edge of paved area at lower level.407 Vegetation: slow running, good visibility.404 Rough open land with scattered trees. ![]()
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