Visualizing a Landscape

In Lesson 3, we discussed map projections—the act of transferring the three-dimensional Earth onto a two-dimensional map. We also presented the flow map symbolization to represent movement. In this lesson, we discuss similar problems—representing Earth’s three-dimensional terrain surface on a two-dimensional map and how to symbolize movement.

When artists depict three-dimensional landscapes, they commonly use an oblique view. See the example painting in figure 4.1.1—the perspective of the drawing makes the landscape appear three-dimensional, though it is only a two-dimensional piece of art.

Figure 4.1.1: A painting of the Southern Appalachians.

Credit: U.S. Department of Agriculture (USDA)

Whether in an artists’ rendering (figure 4.1.1), photograph (figure 4.1.2), or digital model, the oblique perspective is effective in its realism: it depicts what might be seen by a person on or near the ground.

Figure 4.1.2: An image from near Stony Dome in Denali National Park, Alaska.

Credit: U.S. National Park Service

Though the oblique view can create a compelling visual experience, it has its disadvantages. First, this perspective inherently obscures some of the landscape—tall features like mountains or skyscrapers can hide the features behind them. Secondly, oblique views are often constructed by exaggerating the height of landforms so as to emphasize variation in topography. This can make between-map comparisons challenging, and cause issues for cartographers hoping to take accurate measurements with such maps.

Figure 4.1.3: A Map by Heinrich Berann, a Cartographer famous for his panoramic designs.

Credit: U.S. National Park Service

Figure 4.1.4: An oblique-view terrain model of Mars.

Credit: NNASA Mars Exploration Program

To account for these shortcomings, several vertical view techniques for depicting terrain were developed. figure 4.1.5 shows a topographic map from the United States Geological Survey (USGS), which depicts a section of Acadia National Park. Topographic maps are maps that quantitatively depict terrain, typically with contour lines. Contour lines on a map connect points of equal elevation, and when drawn, they visualize hills, valleys, and other landforms. In the next sections, we discuss in further detail techniques for using both oblique and vertical map views to represent Earth's terrain.

Figure 4.1.5: A Topographic map from the USGS, Acadia National Park.

Credit: USGS Mapping the National Parks