YOU can often make your scatter plot communicate more effectively by changing one of the following:
• You can mark the points with a symbol.
• You can connect the points with a line.
To do either of these, use the Color & Lines page of the 3D Plot Format dialog box
To specify the type of marker your plot will use, select an option from each of the following drop-down lists:
• Symbol: Each point in the scatter plot is marked by a symbol. Select among o’s, x’s, +’s, boxes, and diamonds. You can also select “none”; however, if you do and you aren’t using a connecting line, your plot will be blank.
• Color: The markers can be any of the colors listed on the drop-down list, for
example, red, blue, green, magenta, cyan, brown, black, and white.
• Size: Markers can range in size from 1 (thinnest) to 10 (thickest).
The same plot with markers formatted in several ways
If you are plotting data that shows progressive movement in a direction (for example, points in a trajectory), you may want to connect the data points with a line. Mathcad provides several options for connecting the data points:
• No line
• The order in which the points occur in the matrix (row order)
• Increasing x values
• Increasing y values
• Increasing z values
Use the buttons in the Connectivity group to choose which of these options Mathcad should use to connect the data points. Once you’ve decided on the order for connecting the points, you an specify the way the line connecting them will look. Use the buttons in the Line group to choose:
• Style: The connecting line can be solid, dashed, dotted, or alternately dashed and dotted. You can also select “none”; however, if you do so and aren’t using markers, your plot will be blank.
• Color: The lines can be any of the colors on the drop-down list.
• Weight: Lines can range in size from 1 (lightest) to 10 (the heaviest).
The same plot connected in different orders
The Axes page of the 3D Plot Format dialog box lets you modify the format of the x, y, and z axes 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 scatter plot with and without grid lines
To add or remove numbers for the tick marks on an axis, use the Numbered check box for that axis. The plot with grid lines in Figure 25-5 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 1 to 99 in the No. of Grids text box. This text box is only available when Auto Grid is unchecked. By default, Mathcad sets the axis limits according to the data ranges in the three input vectors. However, you can set these limits by hand as follows:
• Click on the Autoscale box in the appropriate axis columns of the Axes page to uncheck it.
• Enter the maximum and minimum values in the Max. Val. and Min. Val. text boxes.
Fixing the axis limits in this way is useful when you are comparing plots of related data sets or setting up an animation sequence.