By default, only the world outlines are displayed when you first start the IDV. You can change the default to use other system maps, or add in your own. The IDV can use McIDAS map files and ESRI shapefiles for map backgrounds.

1. Click on the Default Background Maps link in the Side Legend panel to bring up the control window in the Dashboard and select the Maps tab of the map display control.
2. For each map in the widget, you can control the visibility, the line width, the line type, and color.
   • Change the color of the North & Central America map to green and set it visible.
   • Set the width of the World Coastlines map to 3 pixels wide.
   • Set the width of the World Coastlines map back to 1 pixel wide.
3. When you are finished, save this as the default settings using the File→Default Maps→Save as the Default Map Preference menu in the Default Background Maps control.

You can also display latitude and longitude lines and labels. In the Lat/Lon tab of the map display control, You can set the visibility, interval, base value, line width, line style and color. You can also display latitude and longitude labels.

1. To display the latitude/longitude lines and labels, you can turn on the Lines buttons and the Labels buttons. The link button which is on on default will apply any changes to a latitude or longitude line to the other line.
   • Change the interval to 10 for latitude when the link button is off.
   • Change the interval to 20 for longitude when the link button is on.
   • Change the color of the label to green and alignment to NE.
   • Turn on and off the 0-360 button to use 0 to 360 or -180 to 180 convention for longitude labels
2. When you are finished, you can turn off the Lines buttons, the Labels buttons and the 0-360 button. We are not going to use this setting in the following sessions.

Unidata IDV Workshop for version 5.7 > Starting the IDV/GUI Basics > IDV Basic Concepts