7.5 Map Projection

To change the map projection used to draw satellite data, overlays and the continental outlines, activate the menu of the View button. Most of the entries in this menu are predefined projections that are good for viewing certain types of satellite data. Choose one of these by dragging the cursor of the desired entry and releasing the right mouse button.

If one of the predefined projections will not suffice, choose the last entry in the menu, Arbitrary. A new window will appear with two distinct regions. At the top is the map area. Below the map area are controls that change the map projection. Any time one of these mechanisms is changed, the map is updated to reflect the change.

The two sliders in the control area labeled Pole Latitude and Pole Longitude set the coordinates that appear at the center of the map area. The list of Map Projection Styles that appears below the sliders allows the user to change the type of projection. Hold down the right mouse button on the down arrow and the full list will appear. Move the cursor to the desired choice and release the mouse button. The map will be redrawn using the new projection. When you are satisfied with the view, select the button labeled Set. The popup window will disappear, and the image area of the satellite image window will be updated, using the new map. If you change the map projection while zoomed in, the results may be a bit unpredictable. This unpredictability is due to the way NCAR Graphics handles different projections and will hopefully be remedied in the future.

Note: The Hammer projection works only at the University of Washington.