Teaching Spatial Concepts with Drive-Time Buffers

Blog Post created by jkerski-esristaff Employee on Jun 13, 2013
Teaching spatial concepts and analysis can be effectively done with web-based GIS tools.  One type of spatial analysis involves the use of buffers--areas that show proximity to mapped features.  One kind of buffer is a “drive time” or “service area” buffer, which can be used to calculate and display the amount of time required to walk, bicycle, or drive to or from a certain location.  This developer map is also useful for teaching  to create some buffers, in this case, drive time.

1-2-3 minute drive time buffers

Click on a location in the city of Lawrence, Kansas and wait a moment for the drive time buffer to appear.  Ask the students:  Why aren't these buffers a perfect circle?  Click on Interstate Highway 70 and note the differences between the buffer along this limited access highway versus a buffer along city streets.  Click on a point just north of the river and note the effect of the river that blocks quick access to areas south of it.

These drive time buffers depend not only on the street location and density, but they have intelligence beyond street location:  They take into account one-way streets, stop signs and stop lights, traffic volume, speed limit, physical barriers, and terrain.  Pan the map to a rural area outside Lawrence and click on the map in that location.  What is the difference in the amount of terrain someone could reach in 1, 2, and 3 minutes from a rural area versus that from an urban area?  Why do these differences exist? Pan to the location where you live and calculate drive time buffers in different locations in your own community.

For an application of this concept in analyzing access to a specific type of business, access this map showing pizza restaurants that are within a 3 minute drive of the location you select.  Click on various locations and note the differences in the buffer and the resulting selected restaurants.  This service uses a Yahoo! Local Search to calculate its drive time, but also note that terrain is still important.  In other words, yes, physical geography still matters!

Both of these live maps and the services they provide are easy to use, fascinating, and can foster much good discussion about the practical application of spatial thinking and analysis.