Quick and Simple Graphs

The best introduction to making graphs with PlotIT is through the Quick command. This command is found in the File pull-down menu in the main PlotIT window.

Selecting Quick

Select Quick from the PlotIT File menu. PlotIT will display a dialog box similar to this:

This example will use the Quick defaults. We will deal only with data from which PlotIT will create a graph.

Data Options

As mentioned earlier, data may be in several forms, including a data file or expressed as a mathematical function written in FORTRAN syntax with evaluation limits in brackets. For this example, the FORTRAN function option will be used for data.

To have PlotIT graph the parabola described by y=4x2, it must be written according to the rules of the FORTRAN programming language:

Y=4*X**2

Y=4*X^2

[X-MIN, X-MAX, X-INCREMENT OR NUMBER OF POINTS]

Y=4*X**2 [-20.0, 20.0, 41]

If, as an alternative, you were to enter

Y=4*X**2 [-20.0, 20.0, 1.0]

Entering the Data

Enter the FORTRAN equation and bracketed information into the Data File text box of the Quick dialog box. Take care to get the syntax correct, as illustrated below:

When you have confirmed that you typed the data information correctly, press the Enter key. PlotIT should then display the following curve:

Hint: Use the Windows Maximize buttons to enlarge your graph for better viewing.

Customizing a Quick Graph

Quick graphs may have options that will change their look and offer more information to the person reading them. To help you become more familiar with the way PlotIT works, the following tutorial will take the simple graph created above, and change its look and add information to the graph without changing the data.

Comments

One of the elements that can be included in a graph is a comment. A Comment can simply be an annotation positioned anywhere on or about the graph, or if Auto Graph Title is selected in the Format dialog box, PlotIT will automatically position that comment as a graph title.

Adding a Title

From the Menu Bar, select Graph/Add Element, as shown below.

When the dialog box appears, click on the Comment button, then position the cursor in the New Element Name text box, and type

Title

Your window should look something like this:

Click OK, and notice the new dialog box appears titled with the new element name, Comment 1 Title.

Click on Graph Title. This tells PlotIT that it should position this comment as a graph title. Click on the text box and type a graph title, such as

PlotIT Example 1--Parabola

The comment may be repositioned by using the mouse to click and drag to any desired location.

Manipulating the Comment Element, "Title"

Now that your first graph has a title, let's play with it to understand better how PlotIT works.

Selecting an Element

To select the element "Title", you may click on it with a mouse or use the Menu Bar option, Select. With either method you use to select a graph element, when it is currently selected it will have a check mark by it in the Select menu. The selected element is also displayed in the PlotIT window caption.

Open the Select pop-up menu and verify what graph element is currently selected.

Modifying the Curve Element's Class and Type

Select the curve. (Either point and click on it near a point, or use the Select menu.)

Then select the Format command. (Double-clicking on the curve near a point short-cuts this by selecting the element and bringing up the Format dialog box.) The following is what you should see:

The Class, Type, and Color options should be the defaults specified by Quick, which, in this case, are Line Graph, Trace, and blue. To change the curve to a Point Graph in a shade of green, do the following:

1. Open the Class options drop-down list box by clicking on the down arrow to the right of Line Graph in the Class box. You will see a range of Class options:

2. Select Point Graph.

3. Open the Type drop-down list box by clicking on its down arrow. Select the type, Needle.

4. Then open the color options drop-down list box. Scroll down through the colors by clicking on the scroll down arrow or by moving the thumb scroll down the scroll bar.

5. When green is displayed, select it.

6. Close the dialog box by clicking on OK, and your changes should appear on the graph:

Experiment with other curve Class options, for example, Bar Graph or None. Some options will produce no curve for the data given. When this happens, you can go back into the Format command and choose a Class option that will produce a visible curve.

Hint: Remember that any graph element you wish to modify must be selected, and the Select menu can both confirm which element is currently selected and change that selection, if necessary. If an invisible element is no longer selected (such as our curve element with a class option None, which doesn't create a curve), you must use the Select menu to select that element for modification or deletion.

Adding a Second Curve to the Graph

You may want to display two or more curves in the same graph. The following steps will walk you through adding another curve element to an existing graph.

For this example, we'll plot another function on the parabola graph created in the first tutorial.

1. Add the new element, a second curve, to the graph by selecting Graph/Add Element.

2. Select the curve option in the 2-D Graph section.

3. Give the new element a name by typing it into the New Element Name text box. Your screen should look like this:

4. Click OK or press Enter. A new dialog box appears.

5. At this point you have the option of changing the curve Class and Type from the default Line Graph and Trace. For now, use the default options.

6. Before leaving this dialog box, you must enter a data file name or a FORTRAN equation in the Data File text box. We will use another FORTRAN equation. Type the following

Y=1600-4*X^2 [-20.0, 20.0, 41]