CIR Interpretation Tutorial
Transportation Features in Virtual Nebraska
Most runways are constructed in the direction of the prevailing wind. Although not critical, this design consideration allows for the wind to assist in take-offs and landings, giving the pilot more control over the aircraft. Notice the different colors of the runways. The two major runways (oriented N-S and NNW-SSE) are darker than the others. This is because the darker runways are asphalt, while the lighter ones are concrete. Concrete is more reflective in all of the wavelengths represented by this color infrared image than the asphalt because off their differing physical properties.
Many trains make their way through Nebraska. Most of the trains carry frieght, although there are some passenger trains that also make their way through. Of the many train yards in Nebraska, perhaps the most notable is the Union Pacific Railroad's Baily Yard which is located in North Platte. The Baily Yard was listed in the 1995 edition of the Guinness Book of World Records as being the world's largest rail yard. The train yard covers 2,850 acres, sorts 3,000 cars daily with about 10,000 railroad cars passing through the yard each day. The grayish-blue lines that you see laying across the zoomed-in image are the train tracks themselves. You can easily spot the tracks as they make their way through North Platte. Train tracks often appear on images as bnuish-green (cyan) lines and appear similar to roads. The biggest difference between train tracks and roads is that tran tracks will pass through farm fields, rather than go around their border. Another big difference between train tracks and highways is that highways have on- and off-ramps, while train tracks do not. Trains will never just turn onto, or turn around. They must arrive at a suitable facility where the engines can be turned around to go back in the direction from whence they came.
Freeways and Roadways
Most of the roads in towns are covered with asphalt and are generally darker in appearance. Some roads are not covered in asphalt, revealing the concrete from which they are constructed. As you can see in the figure below, the concrete surfaces are much brigher than the asphalt ones. This fact makes it relatively easy for someone to tell the two surfaces apart.