This app purpose is to calculate a distance between where the user is and any target he wishes to aim at.

It uses basic trigonometry to do the calculations hence working as a passive way of estimate a distance (in opposition to active devices like, for instance, infrared sensors).
It has theoretically no limitations and the results are extremely dependent of the device sensors quality.

The results are extremely dependent of the device sensors quality and, in the app's info panel, there are some advices that may mitigate this problem.

Once again, THE CALCULATIONS WERE PROPERLY TESTED AND VERIFIED, ARE WORKING AS SUPPOSED BUT ARE EXTREMELY DEPENDENT OF THE DEVICE SENSORS QUALITY. If in 2050 there's a manufacturer that finally makes a good compass and GPS sensors, this app will be more precise then than today. Actually, Hipparchus developed trigonometry during is lifetime (190-120BC) and if this app were created and compiled at that time, it would be as accurate as the devices sensors permit at that time as well (irony, predicting bad app rates on the store).