Mapping Our World
You want to plan a camping trip for the weekend. What will you need besides your gear? First, you’ll need to consult a weather map to see if your trip will be rained out. Then you’ll need a road
map to guide you to your destination. Once there, you’ll need a topographic map to help you figure out the lay of the land. Maps such as these are important scientific tools with numerous applications.
Maps are models of the surface of Earth. A model is a representation of an object or thought. Most maps are flat models and thus are two-dimensional representations of a three-dimensional world. You’ve
already seen how weather maps, road maps, and topographic maps can be used in daily life. Other types of maps provide detailed information about soil, vegetation, the oceans, and the stars in the night
sky. Let’s examine how a map is made.
Robinson Projection
Maps are made by projecting points and lines from a globe’s surface onto a sheet of paper. A common type of map projection is the Robinson projection. In a Robinson projection, lines of latitude are
parallel and lines of longitude are semicircles. You may recall that a Mercator projection shows lines of longitude as parallel, which results in distortion near the poles. Because a Robinson projection
shows lines of longitude as true semicircles, this type of projection results in less distortion in the shapes and areas of landmasses. If there is a large world map on your classroom wall, it was very
likely made using a Robinson projection.
Map Uses
Using computers, some maps can be depicted in three dimensions. This type of map offers a more accurate representation of features on or beneath Earth’s surface. Often, such 3-D maps are used in conjunction
with the Geographical Information System (GIS). GIS is a computerized system that analyzes information about a variety of land-use situations. For example, GIS may be used to help city officials choose
the best site for a landfill, to help a park service decide where to build a campground, to help a coal company plan a mine, or to help a disaster-relief group select an accessible site for a storm shelter.
In each situation, data and maps about the sites in question are entered into the GIS computers. The data might include the elevation of the site, its climate, its position relative to populated areas,
and other pertinent facts. Scientists sometimes use GIS together with the Global Positioning System to chart and interpret information on the environment or on Earth’s limited resources.
LINK-UP: Find out more information about GIS.
Mapping Space
Maps are also used by scientists to learn more about our neighbors in space: the planets and the moons. For example, the Mars Orbiter Laser Altimeter (MOLA) is a satellite that uses remote
sensing to map the surface of Mars. MOLA is equipped with technology that transmits infrared laser beams toward Mars. Computers onboard the satellite then record the time it takes for the reflected
beam to return to the satellite’s receiver. The distance to the Martian surface is calculated using the known speed of light and the return time of the laser signal. The resulting data are entered into
computers to create topographic images of the surface of Mars. MOLA has given scientists a much clearer and more accurate view of the rocky Martian landscape.
Activity
Use a road map to plot two different routes to a destination of your choice in the continental United States. First, attempt to plot the shortest route in terms of distance. Then, attempt to plot
the shortest route in terms of time. Keep in mind that average travel time on secondary roads is usually slower than that on primary highways.
