Topography
As you know, the surface of the Earth is not flat. Some places are high and some places
are low. For example, mountain ranges like the Sierra Nevada in California or the Andes
mountains in South America are high above the surrounding areas. We can describe the
topographyof a region by measuring the height or depth of that feature relative to sea
level (Figure2.5). You might measure your height relative to your best friend or classmate.
When your class lines up, some kids make high “mountains” and others are more like small
hills!
Figure 2.5: Topographical map of the Earth showing North America and South America.
( 1 )
What scientists callreliefor terrain includes all the major features or landforms of a region.
A topographic map of an area shows the differences in height orelevationfor mountains,
craters, valleys, and rivers. For example,Figure2.6shows the San Francisco Mountain area
in northern Arizona as well as some nearby lava flows and craters. We will talk about some
different landforms in the next section.