Table of Contents
- Demand-Based Site Selection for Fire Stations Using a Network Allocation Model
- Setting up Your Workspace
- Preparing the Data
- Skill Drill: Clip the Roads Layer to the City of Arcata and McKinleyville
- Skill Drill: Add a Time Cost Attribute to the Roads Layer
- Skill Drill: Creating a CSV Table to Import As XY Data
- Skill Drill: Geocoding an Address and Creating a CSV Table to Import As XY Data
- Skill Drill: Adding the Fire Incident History as XY Data
- Creating A Network Dataset
- Setting up a Network Allocation Model
- Loading Facilities into the Model
- Loading the Demand Points into the Model
- Adjusting the Analysis Setting of the Model
- Running the Network Allocation Model
- Skill Drill: Using the Maximize Attendance Problem Type
- Skill Drill: Adding Existing Fire Stations to the Model
- Skill Drill: Creating a Map of the Results
Skill Drill: Using the Maximize Attendance Problem Type
When using the Maximize Coverage problem type, demand weight is allocated evenly among demand points, regardless of position within the response time window. For example, assuming each point carries the same weight, a demand point adjacent to the facility will allocate the same amount of weight as one that is farthest away, near the outer edge of the impedance cutoff. Maximize Coverage is an optimal problem type when demand points are based on population, such as Census block centroids. It guarantees service to the highest number of demand points served within a limited response time window. However, in this scenario, the demand points are not based on population. Instead, demand points consist of a history of incident responses. The demand points are less uniform, with clustering of incidents over specific areas. This clustering might be an important indicator of where services might be needed more often. If so, another problem type, Maximize Attendance, could suit the situation better.
Maximize Attendance calculates allocated demand based on both weight and distance to the candidate facility. Demand points closer to a facility will allocate a larger proportion of weight. Demand points farther from a facility will allocate less weight in proportion to the distance away. As a result, clusters of demand points near a facility will affect the allocated weight. Click on the Location-Allocation Properties button in the Network Analyst Window. Navigate to the Advanced Settings tab. Verify that the Problem Type is set to Maximize Attendance. Also, change the Impedance Cutoff to 5. This will increase the response time window to five minutes increasing the overall number of demand points in the calculation. Leave all other settings as default and click OK.
Once the Problem Type and Impedance Cutoff are changed, run the model by clicking on the Solve button in the Network Analyst Toolbar. The new model will run and the new results will overwrite the previous results in the memory feature classes in the Table of Contents.
Record the results on a second table in Microsoft Excel.
|Five-Minute Maximized Attendance|
|Location||Demand Count||Demand Weight|