# Graph Pad Dialog Operations

To enter the Graph Pad's Define dialog, use the hand to double-click anywhere within the confines of the page (except the title bar). Or, with an unpinned, active pad, choose Define Graph from the Interface or Model menu. The Graph Pad Define dialog is shown in Figure 6-53. Define dialog operations are described in the text which follows.

Figure 6-53 Graph Pad Dialog

Loading/Removing/Exchanging Variables: The Allowable and Selected lists, along with the buttons between the lists, are used to load, remove, and exchange the variables to be displayed in the Graph Pad page. All model variables (stocks, flows, converters) will appear in the Allowable list. Variables to be plotted appear in the Selected list. When a variable has been loaded to the Selected list, it will appear gray in the Allowable list. Here's how to move variables between the two lists:

- Loading Variables: To load a variable to the Selected list, double-click the variable name in the Allowable list. Or, select it, and click the >> button. To select multiple variables, simply drag-select or shift-click (for adjacent variables in the list), or control-click (Windows) or command-click (Macintosh) for noncontiguous variables.

Helpful Hint: If a variable is selected within the Selected list, any variables that you load to the selected list will be placed above the selected variable.

There is a limit of 5 variables within a Time Series or Bar Graph, 2 variables on a Scatter Plot, and 1 variable within a Comparative Graph.

- Removing Variables: To remove a variable from the Selected list, select it. Then, click on the << button between the two lists. To select multiple variables, simply drag-select or shift-click for adjacent variables, or control-click (Windows) or command-click (Macintosh) for noncontiguous variables.

- Exchanging Variables: To exchange one or more variables in the Allowable list for one or more variables in the Selected list, select the desired variable(s) in each list. Then, click on the <-> button. The variables will be exchanged.

Scaling Variables: Within the Graph Pad's Define dialog, you can set the scale for any variable that has been loaded into the Selected list of a Time Series, Bar, or Scatter Plot. If you don't set a scale, the software will automatically set one for you. For any variable or set of variables, you have four basic options: unscaled, locally scaled, globally scaled, and locally unscaled. A double-headed arrow will appear next to each variable in the Selected list, indicating its scaling status. Figure 6-54 illustrates these different options.

Figure 6-54 Variable Scaling Options

To scale a variable from within the Graph Page dialog, you can follow a simple three-step process. First, in the Selected list, select the variable(s) to be scaled. Second, click on the scaling arrow to select a scaling option. Third, set the scale using the Scale boxes and the Set button. The details of this process are illustrated in Figure 6-55, and detailed in the text below.

- Select variables to be scaled: Step 1 is to select the variable(s) you want to scale from within the Selected list. When you do, the minimum and maximum values, according to the current scaling status, will appear next to the word "Scale" in the dialog.

Figure 6-55 Scaling Variables Within the Graph Dialog

- Select the desired scaling option: Step 2 is to select a scaling option. You can set a local scale, which will apply to the current page only. Or, you can set a global scale, which will apply to all pages (as well as Diagram animation), unless it is overridden locally.

To select local scaling, click on the two-headed vertical arrow located to the right of first selected variable in the Selected list. When horizontal lines (a "floor" and "ceiling") appear above and below each arrowhead, you're ready to set the local scale. To select global scaling, click again on the two-headed arrow. Now, the floor and ceiling will encircle the two-headed arrow like a globe. The encirclement means the variable is ready to be globally-scaled. Note that a subsequent click on the scaling icon will return it to its unscaled state - no lines, no circles.

- Set the Scale: As soon as a scaling option is selected, boxes will appear around the Min and Max values (indicating that you now may edit these values), and the Min value will be selected. To execute Step 3, type the desired minimum and maximum values for the scale of the variable(s). After entering these values, click the Set button. You're set!

Unscaling Variables: To remove a scale that you've set for a variable, select the variable in the Selected list, toggle through the scaling options until you return to the original two-headed arrow (no floor and ceiling, no circle), or to the dashed two-headed arrow (indicating globally scaled, but locally unscaled) then click the De-set button. On the page surface, you can un-scale variables which have previously been scaled by using the Dynamite tool. Click on the upper or lower value in the variable's scale (arrayed on the Y axis of the graph). If the variable had been globally scaled, it will become locally unscaled.

Titling a Page: To title a specific page of the Graph Pad, select the text in the Title field of the Graph Pad dialog. Then, type the desired title. The title will appear in the title bar of unpinned Pads and at the bottom of pinned and unpinned graphs. Note that titles will appear at the bottom of the graph when you print a Graph Pad.

Exercising Display Options: As shown in Figure 6-55, the Graph Pad Dialog provides you with four check box display options. These display options are local to the Graph Pad page.

- Show numbers on plots assigns a number to each variable in a time series plot. Showing numbers on plots is useful when printing graphs. Even when you are using a color monitor, numbers can help the user to differentiate the variables being plotted on a Graph Pad page.

- Show Grid places a grid on the background of the Graph Pad page. A grid can make it easier for users to determine numerical values as they inspect a plot visually.

- Thick Lines will cause the lines of a time series graph to be drawn more boldly.

- Make 5 Grid Segments divides the X axis into five uniform segments as opposed to the default four segments.

Adding Pages: Below the Title field is the apparatus for adding pages to a Graph Pad. Once you have loaded variables into the Selected list of the first page of the Pad, the up-arrow in the apparatus will become active. Click on the arrow (next to the word "New") to create a new page. You can add as many pages to a Pad as you'd like. You can click on the up- or down-arrows to move between pages from within the dialog. Or, you can click on the page-turn "buttons" (lower left corner) on the Graph Pad surface.

Setting the Display Range: The Display boxes at the lower left corner of the dialog give you an opportunity to display a portion of the data associated with a simulation run (Time Series only). The default display range is the entire simulation.

By adjusting the From and To values, you can focus on the details associated with a specific part of the simulation run. The From value must be greater than or equal to the From time you have specified in the Time Specs dialog. The To time must be less than or equal to the To time you have set in the Time Specs dialog. The display range setting you make will be local to the Graph Pad page.

Setting the Graph Type: At the very top of the Graph Pad dialog, four radio buttons and a check box allow you to set the Graph type. You can select between Time Series, Scatter, Bar and Sketchable graphs. For each type, the graph can be generated in a standard or a comparative mode. Comparative graphs superimpose the results of one simulation run atop those generated by previous runs.

- Time Series is the default type. In its standard mode, Time Series will graph a set of variables over simulation time (i.e., time is on the X axis). You can display up to five variables on a standard time series graph. In the comparative mode, the output from multiple runs will be displayed for a single variable.

- Scatter plots chart the values of one variable versus another, as these values change over time. The Scatter type allows you to load only two variables to the Selected list, one per axis. The Connect Dots display option available for Scatter plots causes line segments to be drawn between plotted points.

- Bar graphs let you generate output from your model in a dynamic bar graph display. You can display up to five variables within a bar graph. In the comparative mode, as with the Time Series graph, the output from multiple runs will be displayed for a single variable.

- Sketchable graphs allow a user to "sketch out" the expected performance of a variable for comparison versus the actual performance over a simulation run. See the section on The Sketchable Graph for details.

- Comparative graphs, an available option for each graph type, are often used in conjunction with Sensitivity Analysis. When comparative graphs are generated via a sensitivity analysis, a "?" will appear just to the right of the Dynamite in the lower left of the Graph Pad page. A click on the "?" will pop up a journal of the most recent sensitivity setup used to create the graph. This process was illustrated in Figure 6-52.

Helpful Hint: Comparative graphs accumulate data. Periodically, you may wish to clear this data. To do so, click the Dynamite icon in the lower left corner of the graph or position the Dynamite tool somewhere within the confines of the graphing region and click once. For an illustration, and further details, see Chapter 5's section on the use of the Dynamite. Alternately, choose Restore Graphs & Tables from the Map/Model menu. See Chapter 3 for details.