A free app for Android, by TopOntheFly.

Topography On the Fly is a tool that will enable you to create and edit a topographic map quickly. It is designed to work with a GPS receiver and a compatible compass. It is useful for any type of map, but it is especially useful for land surveying and engineering. It is designed to be used in the field, so you can use it with just a compass and a GPS receiver. It is useful for many types of tasks, such as measuring the area of a field or the distance between two points. It is designed to be used with land surveying tools, such as a GPS receiver and a compass.