Studying Earth's Surface

Introduction to Earth's Surface

• Earth scientists must be able to describe the exact positions or locations of features on the Earth's surface.
• Positions often include distances and directions. To determine direction, you can use a compass, which has a tiny magnetic needle that points toward the Earth's magnetic North Pole. Once you have found north, you can find east, west and south, using your compass for reference.
• Topography describes how the Earth’s surface varies in elevation. Mountains form the highest areas. Valleys and trenches form the lowest areas. Both continents and ocean basins have mountains and mountain ranges. They each also have plateaus, plains, and valleys or trenches.
• Mountains form as continents collide and as volcanoes erupt. Mountains are worn away by wind and water. The earth's surface is constantly changing due to these creative and destructive processes.

Modeling Earth's Surface

• Maps and globes are models of the Earth’s surface. There are many ways to project the three-dimensional surface of the Earth onto a flat map. Each type of map has some advantages as well as disadvantages.
• Most maps use a geographic coordinate system to help you find your location using latitude and longitude.
• Globes are the most accurate representations, because they are round like the Earth, but they cannot be carried around easily. Globes also cannot show the details of the Earth's surface that maps can.

Topographic Maps

• Topographic maps are two-dimensional representations of the three-dimensional surface features of a given area. Topographic maps have contour lines which connect points of identical elevation above sea level.
• Contour lines run next to each other and adjacent contour lines are separated by a constant difference in elevation, usually noted on the map. Topographic maps have a horizontal scale to indicate horizontal distances. Topographic maps help users see how the land changes in elevation.
• Many people use topographic maps to locate surface features in a given area, to find their way through a particular area, and to determine the direction of water flow in a given area.
• Oceanographers use a special type of topographic map called a bathymetric map, which shows the bottom of any given body of water.
• Geologic maps display rock units and geologic features of a region of any size. A small scale map displays individual rock units while a large scale map shows geologic provinces.

Using Satellites and Computers​​​​​​​

• Satellites give a larger view of the Earth's surface from high above. They make many types of measurements for earth scientists.
• A group of specialized satellites called Global Positioning Satellites help people to pinpoint their location.
• Location information, satellite views, and other information can be linked together in Geographical Information Systems (GIS).
• GIS are powerful tools that earth scientists and others can use to study the Earth and its resources.