This page helps you find the distance to a point that you can't measure directly. If you're running this from a smartphone, you can take the data using this page. If you have other means of taking gps locations and compass headings, you can plug the results into the form fields above.
We'll call the point you can't reach the target point. Here's the process:
- Pick 2 "baseline" points that you can get to, that you can get a GPS reading from, and that have visiblity to the target point.
You'll get the best accuracy when the two points are far enough away from each other that they have substantially different view angles to the target; 20° or more is ideal. Smaller angles will work, but the distance measure won't be as accurate.
- Go to the first baseline point. Aim your phone at the target (site the target so that it lines up with the center of the top of the phone) and hit the "capture" button on row A.
- Go to the second baseline point. Aim your phone at the target (site the target so that it lines up with the center of the top of the phone) and hit the "capture" button on row B.
- Once you've captured both baseline points, the app will calculate the distance from the second baseline point to the target, in meters. It will also show the baseline distance and plot all points on the map at the bottom of the page.