GlidePlan gives glider pilots the ability to plan their cross-country flights. It gives you complete control of the flight parameters that create the contour rings. Set the glide ratio and arrival altitude you feel comfortable with given your skill level. As you gain experience, you can tweak the parameters to your liking and print new maps. Perhaps you want an emergency map in the cockpit that shows aggressive glide and arrival altitudes and includes every usable landout. Perhaps you are flying in a new area or with a rental and want a map that reflects conservative thinking.