Topographic Maps and Ratios: A Study of Denali
Topographic maps offer many uses and engineers must know how to navigate them. This Google Earth image shows a topographic map with satellite imagery of Denali, a peak in Alaska.Copyright 2017 Jake Schell, University of Wyoming
Students overlay USGS topographic maps into Google Earth’s satellite imagery. By analyzing Denali, a mountain in Alaska, they discover how to use map scales as ratios to navigate maps, and use rates to make sense of contour lines and elevation changes in an integrated GIS software program. Students also problem solve to find potential pathways up a mountain by calculating gradients.
Engineers use ratios, rates and GIS with great frequency and must be able to work with them in various forms. Often, engineers combine physical documents with technology to make the data easier to understand and manipulate. In addition, technology helps engineers increase efficiency and problem solve while simultaneously globalizing businesses and services. The concept of slope or gradient is ubiquitous in mathematics and applies to all STEM fields. For example, when designing a road in mountainous terrain, civil engineers analyze slope to make the road passable while considering costs, while environmental engineers simultaneously assess the slope and terrain type above and below the road for safety purposes.
After this activity, students should be able to:
- Compute unit rates of contour lines.
- Use rates to understand the growth of mountains.
- Determine whether contour lines are proportional.
- Calculate a grade (gradient/slope).