Introducing Geographic Information Systems with ArcGIS: A Workbook Approach to Learning GIS, 3rd Edition

Finding the Shortest Route to a Facility

Suppose that an automobile accident occurs and routes from the closest hospitals for ambulance service are needed quickly. Network Analyst can provide this information almost instantly.

____ 24. Add as data to the map the data set Hospital.shp, found in

IGIS-Arc_YourInitials\Network_Analyst_Data\Route_&_Allocate\Layers

Zoom to that layer. Make the symbol for a hospital green, with a size 12.

____ 25. In the Network Analyst toolbar drop-down menu, click New Closest Facility. Note that headings for Facilities, Incidents, Routes, and three kinds of Barriers appear in the Network Analyst window.

____ 26. Right-click Facilities (0). Choose Load Locations. In the window that appears, choose Hospital from the Load From drop-down menu. Click OK. Notice that several hospitals appear on the map with the symbol indicated in the Table of Contents under Closest Facility > Facilities > Located. These are, of course, in the same locations as the Hospital layer you added earlier. Facilities (0) should become Facilities (9).

FIGURE 9-20

____ 27. On the Network Analyst Window make sure the drop-down menu is set to Closest Facility. Right-click the text Closest Facility and click Properties to bring up a Layer Properties window. Select the Analysis Settings tab. Make the Impedance Minutes. Under Facilities To Find, change the number to 3. Travel ...