Break On Through to the Other Side: Routing Around Barriers

Blog Post created by jkerski-esristaff Employee on Jul 11, 2013
I recently created a set of activities based on using web-based GIS tools to teach spatial thinking using drive-time buffers, a set of activities that use viewsheds as a teaching tool, another on the use of zonal statistics, and another on analyzing the best route to a facility.  Each of these shares common elements:  They are all based on Esri GIS technology.  They are all free, easy to use, powerful, and they foster spatial thinking.  Let's use another GIS tool to investigate routing around barriers.  Barriers may be physical, such as ridges or rivers, or they may be a human construct or consequence, such as one-way streets, road repair, or an accident.

Routing around barriers

Examine the routing around barriers mapping application.  Let's say you are running a bicycle courier service in downtown San Diego.  Your pick up point is at 1st Avenue and Market Street.  Your destination is at 10th Avenue and Market Street.  Add these 2 stops and have the map calculate your route, shown in blue.  But now say there is construction at 7th Avenue and Market.  Use Add Barriers and add a barrier at 7th Avenue and Market (3 blocks due west of 10th and Market).

What changed on your map after you added a barrier, and why?  Experiment with additional barriers in different locations around downtown San Diego.  Zoom out and repeat the operation with a slightly different scenario at this new scale:  Now you're in a truck filled with trees that you must deliver around metropolitan San Diego.  How can you most efficiently deliver your trees to 4 urban gardens around the city?  Add barriers and observe how they change your route's pattern.  How much additional time do you estimate would be required to make your deliveries with these new barriers?

How might you be able to use this tool in your instruction to foster spatial thinking?