Topo Maps

User Guide

10: Visibility Mode

Visibility mode uses the app's terrain data to compute what should be visible from a particular viewpoint. Simply place the crosshairs over the viewpoint and touch the Visibility button; the app will paint over the map with the hidden areas in red:

This is of course limited by the resolution of the data. In particular, note that to avoid errors in the data near the viewpoint (which would have a more substantial impact on the results than errors further away), the app computes the view from 30m about ground level and ignores all obstacles within about 400m of the viewpoint.