Distance and track cursor

Digital Atmosphere has a sophisticated interface for measuring distances. Simply drag the mouse: hold down the left mouse button at your desired start point, and move the cursor across the screen. You will see a bounding box, and within that, a great circle path (see the illustration). Also in the status bar at the bottom of the screen you will see path data appear, . When you let go of the cursor, the bounding box and great circle path disappear, but the latest path data remains on the status bar.

Bounding box. This defines a rectangular screen region that is used for certain operations within Digital Atmosphere, most notably quality control (File > Quality Control).

Great circle path. Within the bounding box, you will see a diagonal line that connects the two corners of the bounding box (your start and end location). It may have a small or great amount of curvature. This is a great circle path: literally the shortest path between the start location and the mouse location. It represents the path that would occur if you found two points on a globe and connected them with a string. Airplanes always try to adhere to great circle paths when routes and weather permit, thus you can use this feature to find the most likely route for long-distance flights. A great circle path may have a curved look at wide map views, especially toward the edges of the screen, due to inherent distortions in the map projection. Only on the gnomic projection would a great circle path be a perfectly straight line (Digital Atmosphere does not support gnomic projections).

Path data. Shows the coordinates of the start and end points for the great circle track, the initial bearing from the starting point, and the distances in nautical miles, statute ("normal") miles, and kilometers

SPECIAL NOTE : If you want to see distance and direction from cities close to the cursor, see Map > Cursor City Distance to get a display of this information. The path data will be replaced by the city information whenever Map > Cursor City Distance is enabled.