Range Card by iDatabook is a tool that creates a range card based on the shooters location using real overhead images. It can be sized to custom distances based on the shooters need.
Included in the app are tools for marking your firing point and pinging it to find distances in
yards or meters. This especially useful when setting up ranges for training your marksmanship skills when rangefinders are not available.
It also includes an angle compensator tool that allows you to input your line of sight distance,
then use the phone as a level to find corrected for Gravity distance.
(*) This app uses GPS: Continued use of GPS running in the background can dramatically decrease battery life.