Mathcad gives you control over many of the visual characteristics of vector field plots.
These can be categorized in three groups:
• Axis formatting: whether to show tick marks or grid lines on each axis.
• Title characteristics: how the plot will display titles.
To change any of these plot characteristics, start with the 3D Plot Format dialog box:
• Click on the plot to select it.
• Choose Graph~3D Plot from the Format menu. Alternatively, double-click on the plot itself. Mathcad brings up the 3D Plot Format dialog box. The Axes Page of this dialog box is shown below. The remaining tab takes you to the Title page.
The View and the Color & Lines pages are not used for these plots.
• If necessary, click the tab for the page you want to work with.
• Change the appropriate characteristics in the dialog box.
• To see the effect of your changes without closing the dialog box, click “Apply.”
• When you’re finished, close the dialog by clicking “OK
The Axes page of the 3D Plot Format dialog box, shown below, lets you modify the format of the x- and y-axis of your plot. Each axis is described by its own set ‘of check boxes and text boxes
Mathcad generates grid lines on the plot at the same positions as the tick marks. To choose between using tick marks or grid lines on a selected axis, use the Grid Lines check box. When Grid Lines is checked, Mathcad adds grid lines to the plot.
The same vector field plot with and without grid lines.
To add or remove numbers for the tick marks on an axis, use the Numbered check boxfor that axis. The plot with grid lines in Figure 26-3 doesn’t have numbers on the axes while the plot without grid lines does have them.
You can have Mathcad automatically select the number of grid intervals on an axis or you can specify the number yourself. Grid intervals are the spaces between tick marks or grid lines.
• To have Mathcad select the number of grid intervals, use the Auto Grid check box. When Auto Grid is checked, Mathcad will automatically select the number of grid intervals on the specified axis.
• To specify the number of grid intervals on an axis yourself, enter an integer from I to 99 in the No. of Grids text box. This text box is only available when Auto Grid is unchecked.
Since a vector field plot is made by plotting the elements of a matrix, Mathcad cannot “know” anything about x and y coordinates. All it knows is the vector associated with a particular row and column. By default, the coordinates on the x- and y-axes of a vector field plot will simply be rows and columns.
To change the limits on the maximum or minimum values to be plotted on the x- and y-axis, enter the new limit in the Max. Val. or Min. Val. text box.