Using Topographic Maps to Generate Topographic Profiles
Source: Laboratory of Alan Lester - University of Colorado Boulder
Topographic maps are "plan-view" representations of Earth's three-dimensional surface. They are a standard type of map-view that provides an overhead, or aerial, perspective.
Among the defining features of a topographic map are the contour lines that indicate locations of constant elevation. The elevation interval between the contour lines is dependent on the level of detail provided by the map and the kind of topography present. For example, regions with significant topographic variation might require contour lines separated by 40-100 ft., whereas generally flat-lying regions with little topographic variation might have more broadly separated 10-20 ft. contours.
To an experienced user of such maps, the patterns made by the topographic lines are representative of various landform patterns, such as ridges, valleys, hills, and plateaus.
- Obtain a topographic map.
- Establish a line between two specified points on the map. Call these points, A-A', or X-X', or Y-Y'.
- Lay the edge of a paper strip along the cross-section line, marking the two points, A-A', with tick marks.
- Place a tick mark where each of the contour lines intersects the line of the cross-section. Add notations that indicate the elevations of those contour lines.
- If there is substantial topographic variation along the chosen line, A-A', start by o
Once properly smoothed and checked against the map itself (for elevation details between points), the resulting topographic profile is a representation of the highs and lows of a landscape, between the defined points.
When topographic profiles are used as a base for projections of geologic features into the subsurface, it's generally best to avoid vertical exaggeration - in other words, the horizontal and vertical axes should ha
A topographic profile provides a visual representation of the topographic highs and lows across a line segment on a map, from one point to another. Such profiles are used to evaluate the "ruggedness" of terrain, which is useful in assessing the difficulty of travel (driving, biking, or hiking as transportation modes for field-work) (Figure 1). Sometimes fieldwork requires making a transect through a region for the purpose of collecting samples or making geophysical measurements.
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