Balancing Territories

Balancing territories can be done at various stages of territory design. For example, you can choose to balance territories when creating a territory solution or use the Improve Territories wizard after you have set up your territories. You can also rebalance territories at any time to meet your desired criteria. Variables in your alignment layer or imported variables can be used in the balancing process.

Measuring Distance

Territories can be constrained by distance, with straightline distance, drive distance, or drive time. Using drive distance or drive time uses the underlying streets network and can impact the processing time for creating territories.

You can set the maximum distances a territory can grow and the minimum distances of the center of a territory from other territory boundaries.

Setting Capacity Values

Setting capacity values is an important feature to constrain your territories. A capacity value is a threshold you can set to ensure that a territory does not exceed variable limits. For example, you can specify that all territories must stop growing in area when a population of 150,000 is reached. The 150,000 figure is the capacity value. You can also set a tolerance value if more than one variable is used to create territories. A tolerance value gives a plus-or-minus range of the capacity value and allows more overall balanced territories. For example, if the capacity value is a population of 150,000 and the tolerance is set at 20,000 people, then the range is 130,000 as a floor and 170,000 as a ceiling.

Option 1: Each variable reaches capacity value

Territory creation is stopped only if all variables reach their specified values. As a result, some variables can be much greater than specified.

Option 1 with Tolerance activated: Territory creation stops if some variable(s) reaches the specified value and some variable(s) reaches the floor boundary (specified value minus tolerance).

Option 2: Any variable reaches capacity value

Territory creation is stopped if any variable reaches its specified values. As a result, some variables can be much less than specified.

Option 2 with Tolerance activated: The territory creation will continue while any variable hasn't yet reached the ceiling boundary (specified value plus tolerance) or all variables haven't yet reached the specified value.

注意:

Tolerance values can be in numeric or percent form. Add a % symbol to use a percent value.

Using the Preferences Pie Chart

By default, all variables are weighted equally. The pie chart allows you to change the variable importance of the territories you are creating. Click and drag the separator lines to dynamically change the percentages. The numbers will automatically change in the field view. The percentage must total 100. The distance weight is a significant factor in the development of territories. If you want to balance your territories based on an attribute, such as sales, minimize the distance weight in the pie chart.

As an example, this would be useful if you are a cable TV provider looking to redistrict your franchise areas, which are based on ZIP Codes. You know that having an equal population distribution is key to adequately support your customer base, but you also know that as long as you have enough technicians, the size of the area is not relevant. In this case, you may want to set the population importance variable at a higher percentage and leave the distance factor low. This will increase the probability that the underlying ZIP Codes will be combined to form weighted territories with equal population.

General Balancing Options

• Territories must be contiguous—Checking this option ensures that all geographic objects adjacent to balanced territories are included in balancing.
• No holes inside territories—Checking this option ensures that the balancing algorithm doesn't create blank areas wholly contained inside territories. Any unassigned elements are appended to the surrounding territory. The balancing algorithm doesn't remove holes that were present before starting the Balance command.
• Use unassigned territories—Checking this option ensures that currently unassigned geographic elements are added to territories to improve the balance. Uncheck this option if you only want to swap geographic elements between territories.
• Do not reassign polygons that contain territory centers—Checking this option ensures that territory centers remain in the territory polygons for which they are contained. This is especially important when you have more seed points than territories.
• Use only closest to territory center features— Checking this option ensures the balancing algorithm will reassign a feature to a growing territory only if this feature is closer to this territory center than to other nearby centers.

Compactness

Compactness is the decision between the quality of resulting territories shape and resulting statistical balance. Compactness is controlled through an interactive slider bar.

The best territory shape is often

• Straight Line distance: Circle around territory center(s).
• Drive Time/Distance distances: Shape with minimal traveling time/distance from territory center(s).

How to select the compactness value

Low values of compactness can lead to snake effects and bad performance (compact territories are always calculated faster), but the resulting balance can be ideal. Setting the compactness values of near 100 percent will lead to a nonideal balance but a perfect territory shape and fast balancing process. Setting values near 0 will provide better balanced territories but slower processing and an undesirable shape. These results depend on source data, number of territories, disposition of territory centers, and other considerations. For this reason, you may want to try different values. Here's a recommended scenario:

1. Leave the default Compactness value and start balancing territories.
2. If the balancing process takes acceptable time and the shape of territories is compact, but the territory balancing needs more improvement, then decrease the Compactness value 10–20 percent and balance again. If the shape of territories are not acceptable after the first run, increase the Compactness value and/or change other balancing options using Edit Territory Solution > Improve Territories > Adjust Territory Parameters wizard. This will reset the shape of territories and recreate and rebalance territories from existing territory centers.
3. If time and compactness are still acceptable, repeat step 2. To repeat the balancing alone, use Edit Territory Solution > Improve Territories > Balance Territories. This will continue balancing from the previous state of territories. The ArcMap Undo operation can be used to return to the previous state of territories if the last balance was unacceptable.

During this process, you can use constraining tools (Lock, Extent) to exclude territories or areas where balance is satisfactory.

ヒント:

Click Stop to stop balancing without losing results.