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Purpose: Familiarize students with representations of the Earth through aerial photography and to show how various features on the Earth can be  represented within  a GIS.

There are three ways in which features on the Earth can be represented in a  vector GIS. These are points, lines, and polygons.  Some examples of points might include a lamppost, an oil well, or an individual house on a city block.  Lines could be a number features including roads, rivers, power lines, or a sprinkler system.  The last type of GIS feature is a polygon.  Polygons could be used to delineate a lake, a downtown historic district or an archaeological site.

Once you have created a number of points, lines, and polygon features you can attach attributes to the feature.  Attributes  for some of the previously mentioned examples could be height of lamppost, depth of oil well, or house address.  A road could contain attributes concerning type of road (i.e. paved, two-track, four-lane, two-lane) or amount of electricity flowing through a power line.  Polygon attributes could be name of a lake, time period of a site, etc.

In this excersize you will asked to examine six different aerial photos from around the U.S. and use points ,lines, and polygons to describe certain features in each photo.  You will be asked to draw on the photos and answer 3-4 questions for each photo.  To learn how to download and print the images click here.

Last revised: 13 September 1998 by Timothy E. King   (sl0b7@cc.usu.edu)