Crater Lake, Oregon - 30x60 Minute Series Topo Map Christa Sadler Based on historical records

Based on historical records

an index to geologic mapping used to create the map

There's nothing like tasty

in the words of editor Aubrey L

ground-water compartments

Crater Lake, Oregon - 30x60 Minute Series Topo Map Christa Sadler Based on historical recordsThe distinctive characteristic of a topographic map is that the shape of the Earth's surface is shown by contour lines. Contours are imaginary lines that join points of equal elevation on the surface of the land above or below a reference surface, such as mean sea level. Contours make it possible to measure the height of mountains, depths of the ocean bottom, and steepness of slopes. A topographic map shows more than contours. The map also includes