Topographic maps and Cross sections

• Topographic maps are maps that use symbols to portray how the land is viewed from above.
• Topographic maps provide information on the elevation, relief, and slope of the ground surface, as well as the location of roads, buildings and other features, natural and man-made
• Contour lines on a map show points of equal height above or below sea level.
• A contour interval is the difference in the elevation between two contour lines on a topographical map
• When contour lines are close together this means the area is steeply sloped; when they are far apart this means that the area is gently sloped or flat land.
• Spot heights are points on the map showing the heights of hills
• Benchmarks are marked points of known elevation which serve as reference points from which the height of others places may be established
• Trigonometrical stations are points marked by metal discs mounted on stable foundations such as concrete pillars
• A cross-section represents the shape of the land drawn as if a vertical "slice" were made through the landscape over particular distance.