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profile drawing — English
The process of drawing a side view of a small part of the Earth’s surface to obtain a representation of the relief of the surface. It is done by a simple, relatively primitive technique and all that is needed is a contour map of the area (see “isometric line” and “topographical map”). If a profile of a certain relief feature is required, a line that cuts across that feature and runs between two definite points (call them A and B), such as two trigonometric beacons, on either side of the feature is drawn on the map. The edge of a loose sheet of paper is placed along this line. Wherever the line crosses a contour line, a mark is made on the very edge of the sheet of paper and the altitude (see”isometric line”) of that point on the surface is written down. One then constructs a set of axes on the sheet of paper directly underneath the line of marks along the edge of the sheet. The horizontal axis (x axis) represents the distance between points A and B, according to the scale of the map (say, 1:50 000). The scale for the vertical axis (y axis) is selected by the person who is drawing the profile and – depending on the relief of the landscape – it might be convenient to use something like 2 mm on the drawing to represent 20 m in reality. Point A is plotted on the y axis according to its altitude, and then all the contour-intersection points marked on the edge of the sheet of paper are plotted where their positions on the x axis intersect their altitudes on the y axis. All the plotted points are then joined by one line which visually represents the actual relief of the surface. The feature of interest will be clearly seen on this profile line. This technique is extremely important in geomorphology and geology and in the latter such profiles are usually called “cross sections”.
