NMPlot User's Guide, Chapter 7: Introduction to Plots

A plot is a graphical representation of a grid that displays a combination of the following elements.

• A set of contours representing the grid's scalar field

• Smoothly varying gradients of color representing the grid's scalar field

• A map of the location of the grid's data points

• The grid's geographic annotations

• A background map

This chapter discusses the basics of creating and configuring plots. Later chapters discuss the various elements of a plot in detail.

Creating a New Plot

To create a new plot, follow these steps.

1. Choose New from the File menu, then choose Plot. The New Plot dialog box appears.

   

2. Select the type of plot to create. You have two choices.

   • Create plot of a grid - This is the most common choice. A contour plot of a grid will be created.

     Type the name of the grid file that you want the plot to display. Press the Browse button , located to the right of the text box, to display the Open File dialog box, which allows you to browse for the file.

   • Create plot showing only a background map - A plot will be created that shows one or more background map layers. No grid file is required. This is useful for previewing the contents of a map file.

     Specify the background map layers that you wish to display. See Background Layers for more information.

3. Press OK. A plot document window appears, displaying the new plot.

The Plot Options Dialog Box

To display the Plot Options dialog box, you can:

• Choose Options from the Plot menu.

• Press the Options button on the toolbar.

Use the Plot Options dialog box to change a plot's appearance. All plot options are set from here.

The left portion of the dialog box displays a list of option categories. One category in this list is always selected. The right portion of the dialog box displays controls that allow you to change the options in the selected category.

The Plot Options dialog box is a Multiple Page dialog box. See Multiple Page Dialog Boxes for more information.

The Primary Grid of a Plot

The purpose of a plot is to graphically display a grid, which is know as the plot's primary grid.

Note:

NMPlot assumes that the primary grid is stored in a file. When a plot is created, you are prompted for the name of the primary grid file. If you later want to change the primary grid, follow these steps.

1. Display the Primary Grid page of the Plot Options dialog box.

   

2. In the box provided, type the name of the grid file containing the primary grid. Press the Browse button , located to the right of the text box, to display the Open File dialog box, which allows you to browse for the file.

To display a plot's primary grid, choose Display Primary Grid of this Plot from the Plot menu. NMPlot will open the primary grid and display a summary of it. See Viewing Grids for more information.

Saving a Plot

You can save a plot to a file, referred to as a plot file . All options on the Plot Options dialog box are saved. Plot files typically have the extension .nmp, which is short for NMPlot Plot.

To save a plot, choose either Save or Save As from the File menu.

Opening a Plot

To open a plot that has been saved to a file, follow these steps.

1. Choose Open from the File menu. The standard Windows dialog box for opening files is displayed. Familiarity with the use of this dialog box is assumed.

2. Navigate to the directory where your plot file is located, then open the file. Plot files typically have the extension .nmp.

3. A Plot Document window appears, displaying the plot.

NMPlot can read all previous versions of plot files.