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

Allocating Territories to Facilities

Assume that you want to do an analysis of how well fire stations can respond. Perhaps a new standard is proposed that every point in the downtown area of the city should be reachable within 1.5 minutes from some fire station.

____ 31. In the T/C, under Layers, remove all layers except Streets, Streets_ND_Junctions, and Streets_nd. Add as data Fire_Station.shp. Make each fire station show up with a yellow circle of size 12. Choose Zoom To Layer.

____ 32. On the Network Analyst toolbar drop-down menu, choose New Service Area. Right-click on Facilities in the Network Analyst window and load the fire station locations. Click OK. How many are there? ________.

____ 33. Click Polygons (0) (under Service Area > Facilities (40)). Click the Service Area Properties text to bring up Layer Properties > Analysis Settings. The Default Breaks field specifies the extent of the service area by calculating how far, along each possible route from the fire station, a vehicle could reach in the time allotted. Set it at 1.5. Respect one-way streets. Click Apply. Under the Polygon Generation tab, read the text of the various options, then click on Generalized if necessay. (If solving the problem with generalized polygons doesn’t take too long, you can come back and ask for the detailed polygons.) Click Apply, then OK.

____ 34. Press the Solve button and be prepared to wait. The software is computing, for each fire station, the 1.5-minute range along each possible ...