Is the straight line the best drone route?

Updated · Flytimizer guides

Short answer: Often not. The straight line at one fixed altitude ignores how the wind changes with height, terrain that pushes you over the height limit or too close to the ground, buildings, and restricted or sensitive sites like schools, hospitals, prisons and airports. A good plan picks a height for each leg, follows the ground, and detours where needed.

Four reasons the obvious route isn't the best one

1. The altitude matters as much as the line

Wind usually gets stronger with height, and the outbound and return legs face opposite winds. The same line can take very different times at 30 m and at 120 m. In this worked example, choosing 30 m out and 120 m back instead of "120 m both ways" cuts a long round trip by 41%.

2. Terrain changes your height above the ground

Legal height limits are above the ground (120 m in the EU, 400 ft in the US). Fly a constant altitude from a coast up a ridge and you may be too low over the ridge, then far over the limit as the ground drops into the next valley. Plan the altitude profile along the whole route, using elevation data.

3. Buildings

Tall buildings on the line either set your minimum height, with a safety margin above the tallest one, or are better avoided with a small sideways detour. A detour can even let you fly lower and faster. A building taller than your height limit has to be routed around.

4. Restricted and sensitive sites

Many countries require you to keep away from schools, hospitals, prisons, power plants, military sites, embassies, and especially airports and heliports. Some are no-fly areas whatever your altitude. A straight line often crosses at least one. Routing around them adds a little distance, but it's the difference between a legal flight and an illegal one.

A quick planning checklist

  1. Check the wind at several heights for the hour you'll fly, and its direction relative to each leg.
  2. Check the gusts against your drone's rated wind resistance at the height you'll fly.
  3. Look at the terrain along the route and plan heights above the ground.
  4. Check buildings and restricted sites along the route, and your local rules and notices (NOTAMs).
  5. Estimate battery for the round trip, with a 20%+ reserve.
  6. Consider flying at a different time if the next few hours are calmer.

How Flytimizer plans the route

Flytimizer does all of this from two points on a map. It looks up schools, kindergartens, hospitals, playgrounds, nursing homes, universities, power facilities, airports, heliports, prisons, embassies and military sites from OpenStreetMap, and detours around them. It checks the buildings on the route, follows the terrain using Copernicus elevation data, and applies the rules of the country you start in (currently Israel and the United States). Then it picks the altitude for each leg from the live wind forecast. You can share the route as a link, and download it as a DJI waypoint mission for DJI Pilot 2.

Map data comes from OpenStreetMap, which can be incomplete. Always check official no-fly maps and local rules before flying.

Plan your route in Flytimizer — free, no sign-up

FAQ

What is the most efficient drone flight path?

The one that minimises time in the strongest headwind while staying clear of terrain, buildings and restricted areas, and within the height limit above the ground. That's often a slight detour, with different altitudes for the outbound and return legs, rather than the straight line at one height.

Can I fly my drone over a school or hospital?

In many countries you must keep a distance from schools, hospitals and similar sites, and airports and military sites are often no-fly areas. The rules vary by country, so check your national aviation authority and its no-fly maps before every flight.

Is the drone height limit measured above the ground or above takeoff?

Above the ground below the drone. In the EU it's 120 m from the closest point of the Earth's surface, and in the US 400 ft above ground level. Over hilly ground, a constant altitude can break the limit over low ground even if it was fine at takeoff.

How do I plan a drone delivery route?

Pick the start and drop-off points, check the wind at several heights and the gusts, choose an altitude for each leg (often lower into the wind), follow the terrain, keep clear of buildings and restricted sites, and check the battery for the round trip with the payload out and back, keeping a reserve. Flytimizer does these steps automatically.