PRE-FLIGHT CHECKS
Draw a route — checks against terrain, the 120 m limit and geozones run automatically.
Terrain: Mapzen/AWS terrarium — in Latvia the source is EU-DEM, a surface model on a
25 m grid (trees and buildings are already in it, but smoothed). It does not resolve a single
tree, a power line or a mast, and over forest it reads lower than the real canopy.
Add a margin and keep visual contact with the drone.