Adjusting Target Weights

You can also describe the relative importance of each target by setting target weights. The weight values prioritize the importance of the objectives for the scheduler, putting more emphasis on achieving certain goals than others. Weights are set much the same as objective levels. To set Weights, select from the tool bar. This places a single black line horizontally across the chart. Like objective values, weights can be set for just maximums, just minimums or both, as well as equally for all periods or individually for single periods. Use the mouse to click above the horizontal line to increase the weight, or below the line to decrease the value of the weight. When in Weight mode, the weights appear in the bottom colour coded boxes for the Maximums and Minimums. You may also enter exact weight values into the red and blue boxes at the bottom of the control.

Targets can be weighted to increase or decrease their importance in driving a solution in the Patchworks model. Weighting is an important tool to prioritize your objectives for the model. Weights can be changed while the model is running to increase or decrease the importance of achieving a particular level, allowing Patchworks to make decisions based on your 'priorities'.

[Important]Apples and oranges!

Since attributes and accounts are represented in various units and scales, weights can also be used to correct scale differences. For example, you might have volume (m3/ha) and area (ha) targets. One hectare of area yields is about 100m3 of harvest volume (rough estimate, but the order of magnitude is about right). If you were trying to scale the targets to equally trade off area and yield, you would set the volume target weights to 1 and the area weights to 100. If you wanted area to be more important than volume, then the ratio would have to be smaller than 1:100 (in your case maybe 1:100000). Note that this is quite subjective, other factors such as scarcity also come into play.

Weights, like target values, can be easily adjusted in either the Target Chart itself or by editing various files. Weights can be added to either the Minimum, Maximum or Both constraints by selecting one of the icons from the chart toolbar. The weighting factors are indicated in the appropriate colour codes boxes at the bottom of the chart when in Weight View . To adjust the weighting factor, click within the target chart itself. Clicking close to the weighting reference line will only create a small change the weight, however the change becomes significantly increased the further from the reference line. By clicking above the reference line the weighting factor will increase, whereas by clicking below the line the factor will decrease based on the distance from the reference line.

An exact weight can be applied to a target by typing a value in the appropriate box at the bottom of the chart. Weight values, like target values, can be applied to either the entire time horizon or to individual periods by selecting either from the toolbar. For example, it may be most important to maintain a minimum amount of a particular habitat over a certain amount of time. To make this 'priority' known to the Patchworks model and to balance with other accounts the minimum value for the habitat may be weighted 1000 times higher than any other target only for specifed periods. In this case decisions would be made by the scheduler to ensure the minimum amount of habitat is maintained at the expense of various other targets.