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NMPlot User's Guide, Chapter 8: Working With Plots

Mouse Location Displayed On Status Bar

To determine the geographic coordinates of a location on a plot, point to that location with the mouse. The coordinates are displayed on the status bar. You can change the coordinate system used to display the location: see Mouse Location Display Coordinates.

If the location is within the primary grid's defined area polygon, the data value of the grid at that location is also displayed. If the location is between grid data points, two-dimensional interpolation is used to compute the data value.

If the location is outside the primary grid's defined area polygon, dashes ---- are displayed for the data value.

The coordinates and the data value are automatically updated as the mouse is moved.

Mouse Tools

NMPlot provides a number of tools for working with plots. For example, the Measurement tool allows you to measure the distance between two points on a plot.

To use a tool, you must first activate it by pressing its button on the toolbar. When the mouse cursor is over a plot, the cursor changes shape to indicate which tool is active.

The tools are described in detail in this chapter.

Zooming and Panning

Zooming refers to increasing or decreasing the magnification level at which a plot is displayed.

Panning refers to moving a plot horizontally or vertically, so that previously hidden portions of the plot become visible.

The Zoom Mouse Tool

Activate the Zoom mouse tool by pressing its button on the toolbar. When the Zoom tool is active, you can:

When the Zoom tool is active, you can drag a rectangular area using the left mouse button. The plot is zoomed and panned so that this area fills the plot window.

The Pan Mouse Tool

Activate the Pan mouse tool by pressing its button on the toolbar. When the Pan tool is active, you can drag with the left mouse button to pan the map.

Using the Mouse Wheel

If your mouse has a wheel button, you can use it to zoom and pan the plot.

Roll the wheel forward to zoom in. Roll the wheel backward to zoom out. Hold down the Ctrl key while rolling the wheel to zoom in finer increments.

Pan by pressing and holding the wheel button. A small marker appears at the point where you press the button. While holding the button down, move the mouse cursor away from the marker. The plot pans in the direction that you move the mouse. The farther the mouse is from the marker, the faster the plot pans. Release the mouse button to stop panning.

Alternatively, click and release the wheel button. NMPlot enters panning mode. Move the mouse to pan the plot. Exit panning mode by clicking the wheel button a second time.

Tip:

You can zoom and pan using the mouse wheel regardless of which mouse tool is active. This provides you with a convenient way to zoom and pan while using the other mouse tools.

Keyboard Shortcuts

The following keyboard shortcuts allow you to pan and zoom a plot regardless of which mouse tool is active.

Key Action
  Pan up
Ctrl +  Pan up faster
  Pan down
Ctrl +  Pan down faster
  Pan left
Ctrl +  Pan left faster
  Pan right
Ctrl +  Pan right faster
+   Zoom in
-   Zoom out

The Home View

When a plot is first displayed, it is automatically zoomed and panned so that the "interesting" features of the plot (the contours, the geographic annotations, etc.) fill the plot window. This is called the home view.

If, after scrolling and zooming, you wish to return to the home view, you can:

To change the home view of a plot, follow these steps.

  1. Display the Home View page of the Plot Options dialog box.

  2. Select the method for computing the home view. You have two choices.

    • Specified Plot Elements - The home view fills the plot window with the selected parts of the plot. You may choose any combination of the following parts.

    • Manually Specified Area - The home view fills the plot window with a rectangular portion of the plot defined by two points that you specify. Enter the coordinates of two points that define opposite corners of this rectangle. Select the coordinate system used to specify these points. You have two choices.

      • The primary grid's coordinate system

      • Longitude and latitude, specified in decimal degrees east and north. Note that west longitudes are negative

Plot Orientation

Following mapping conventions, plots are typically displayed with north at the top. However, NMPlot allows you to display plots at any orientation. To set the orientation of a plot, follow these steps.

  1. Display the Orientation page of the Plot Options dialog box.

  2. Select the direction of north. If you select At an angle of, type the direction of north, in degrees clockwise from the top of the plot.

The north indicator at the bottom of the dialog box page displays the direction of north that you have selected.

Note:

If you set a plot's orientation so that the direction of north is not towards the top of the plot, georeferenced bitmap background maps will not be displayed. NMPlot does not currently support the rotating of bitmap background maps.

The Display Properties Mouse Tool

Use the Display Properties tool to display information about objects in a plot. Activate the tool by pressing its button on the toolbar. Click on an object in a plot to display the Properties of Selected Object dialog box, which shows information about the object.

To copy the information to the clipboard, press the Copy to Clipboard button. To copy only a portion of the text, select it (by dragging over it with the mouse) before pressing the button.

Tip:

If you click upon a contour, NMPlot displays the area inside the contour. You can change the units used to display the area: see Physical Units.

Note:

NMPlot cannot display information about objects in background layers.

The Measurement Mouse Tool

Use the Measurement tool to measure the distance and angle between two points on a plot. Activate the tool by pressing its button on the toolbar. To measure the distance between two points, press and hold the left mouse button over the first point, then move the mouse to the second point. The status bar displays the coordinates of the two points, the distance between them, and the directional heading from the first point to the second.

You can change the coordinate system used to display the location of the two points: see Mouse Location Display Coordinates.

You can change the units used to display the distance between the two points: see Physical Units.

The heading is the direction of the second point as seen from the first point, measured in degrees east of true north.

The Point Of Interest Computation Mouse Tool

Use the Point of Interest Computation tool to perform a detailed analysis of the conditions at a specific location on a plot. In order to use this tool, the plot's primary grid must have been created by using BaseOps to run one or more third-party numerical model(s) supported by a client-specific extension to NMPlot. Point of Interest extensions have been developed for the following models.

To use the Point of Interest Computation tool, follow these steps.

  1. Activate the tool by pressing its button on the toolbar.

  2. Using the left mouse button, click on a plot at the location where you want to perform the point of interest analysis.

  3. NMPlot runs the appropriate third-party numerical model(s), instructing them to perform a detailed point of interest analysis at the indicated location.

  4. The results of the analysis are displayed in the New Point of Interest dialog box.

  5. The results of the analysis are added to the plot's primary grid as a point geographic annotation. When you close the plot, you are given a chance to save the modified primary grid in a file.

See Client-Specific Extensions for more information about client-specific extensions to NMPlot. See NOISEMAP Client-Specific Extension for more information about the NOISEMAP client-specific extensions.

The Grid Computation Mouse Tool

Use the Grid Computation tool to increase the resolution of a grid by merging additional data points into it. In order to use this tool, the plot's primary grid must have been created by using BaseOps to run one or more third-party numerical model(s) supported by a client-specific extension to NMPlot. Grid Computation extensions have been developed for the following models.

To use the Grid Computation tool, follow these steps.

  1. Activate the tool by pressing its button on the toolbar.

  2. Using the left mouse button, drag a rectangular area on a plot where you want to increase the resolution of the plot's primary grid . That is, move the mouse to one corner of the rectangular area, press and hold the left mouse button, move the mouse to the opposite corner of the rectangular area, and release the mouse button.

  3. The Run New Grid dialog box appears.

    Type the resolution of the data points (i.e., the distance between adjacent data points) you want to merge into the primary grid.

  4. Press the OK button. NMPlot runs the appropriate third-party numerical model, instructing it to create a new grid with data points distributed on a two-dimensional rectangular grid of locations. The area covered by this new grid will be the rectangular area that you specified using the mouse. The distance between adjacent data points will be the resolution you specified in the Run New Grid dialog box.

    The new grid is automatically merged into the primary grid, and the plot is updated.

  5. When you close the plot, you are given a chance to save the modified primary grid in a file.

See Client-Specific Extensions for more information about client-specific extensions to NMPlot. See NOISEMAP Client-Specific Extension for more information about the NOISEMAP client-specific extensions.

Tip:

Use the Grid Computation tool to increase a grid's resolution in areas where a contour plot of the grid appears ragged, or where the contours break up into unconnected islands. This will often improve the appearance of the contours.


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