How to know your drone is of the same level as the building?

[Daniel2300]

How to know your drone is of the same level as the building?
If you want to fly over a building safely, but you do not know uts height.
How to judge that your drone is higher thanthe building without using obstable avoidance.

 

[mavic3usa]

it depends on whether you are flying visual line of sight or not. unless i am flying fpv, i like to clear the tops of buildings and other structures by at least 20 - 30 feet so with the camera tilted somewhat downward, if i can see all sides of the top of the building to confirm what i see visually.....

 

[DoomMeister]

With the gimbal set to 0° objects below the horizon are beneath your altitude, those even with the horizon are at your altitude, and those above the horizon are higher than your altitude. This is good for at least 200’ (60m) which should give you time to react if you are flying at speeds for cinematic video.

 

[Robert Prior]

With the gimbal set to 0° objects below the horizon are beneath your altitude, those even with the horizon are at your altitude, and those above the horizon are higher than your altitude. This is good for at least 200’ (60m) which should give you time to react if you are flying at speeds for cinematic video.

Following on to this…

I would make a scouting flight and note the altitude of any buildings I was planning on flying over, then ensure that I was safely higher than that so I didn't have to worry about it. Especially if I was planning on flying sideways/backwards for some shots, or doing tilt reveals, or anything that would mean that the camera wasn't pointed where the drone was going.

Also be aware that if you use waypoints the drone flies a smooth path between them (I think it's a spline) so it can end up higher or lower than the highest or lowest waypoint to make a smooth curve. This is something you need to consider when making your flight plan.

 

[mavic3usa]

How to know your drone is of the same level as the building?
If you want to fly over a building safely, but you do not know uts height.
How to judge that your drone is higher thanthe building without using obstable avoidance.

I can see from many of your videos that you fly a lot of long distance flights and it appears you have several tall buildings and structures in the area so you want to know if what you are seeing is accurate; I often have similar problem and usually end up going around the building because as I fly uphill, the buildings on top of the hill are even higher so it's tricky for me. I see your concern.

 

[Scout Aerial]

I usually fly my drone up with the camera at 90 degrees and when the top of the roof is in the middle of the screen, I go up another 15-30 feet, to avoid crashing the drone. To conserve my Mavic 2 Pro's batteries, I'll sometimes find this height with my backup Mini 2.

I assume you're planning a mission for mapping or roof inspection. Keep in mind that some buildings have roofs with a height that varies. When I do industrial parks, the roof is usually at a consistent height (although the ground may be higher or lower at different points around the building).

Some of these buildings have (I don't know the architectural term, but) parts of the facade which are raised and stand out from the rest of the building. This is common at shopping centers such as Walmart, but I've also seen it in industrial parks.

And of course, some buildings simply have a sloping roof, so there's something else to take into consideration.

I think there is very little difference between a photo taken at (roof elevation) + 15 feet vs. one taken at +30 feet. It's best to err on the side of caution. In addition to losing a drone, you don't have to explain to a client why you need access to their roof to retrieve a drone.

 

[RodPad]

I like all this info

I started getting lost on this thread, what was the reason the op was asking this?

Rod ..

 

[Felix le Chat]

The method I use to deliberately assess the height of a building before I try to fly over it? As follows.

Drone take-off from ground level (0 feet AGL).

Straight vertical climb with camera at 0 degrees.

Halt when highest point of roof is at the centre of diagonal cross hairs.

Look at on screen AGL readout.

Add 30 feet and climb accordingly.

This is when the building is the focus of the shoot, for a spur of the moment balls-out flyover? Steps 3,4 and 5.

 

[millbah]

I have a similar problem determining height of Telcom towers when doing a mapping mission. The mapping software pre-determines a height, so a height check is sometimes necessary before I start. It is more tricky when dealing with jungle/high trees to get the right height.
I go with the methods mentioned earlier, being bringing the drone up to the object & noting the horizon line. Down side is using up precious battery time.

 

[Dbez1]

With the gimbal set to 0° objects below the horizon are beneath your altitude, those even with the horizon are at your altitude, and those above the horizon are higher than your altitude. This is good for at least 200’ (60m) which should give you time to react if you are flying at speeds for cinematic video.

I agree and would reinforce that if you have the crosshairs switched to “ON” as Felix noted above,, it makes it easier. Give yourself some safety though.

 

[DougMcC]

Here’s a pilot tip from the cockpit. In level flight (camera at 0 degree elevation) objects or edges AS YOU APPROACH that are moving DOWN in the camera (or windshield) will pass below you and anything rising as you approach tells you to climb or avoid. This works for tree lines mountains and buildings.

 

[rfaass]

Here’s a pilot tip from the cockpit. In level flight (camera at 0 degree elevation) objects or edges AS YOU APPROACH that are moving DOWN in the camera (or windshield) will pass below you and anything rising as you approach tells you to climb or avoid. This works for tree lines mountains and buildings.

This is it, same with moving objects, if the angle you see them is stationary, you are on collision course.

 

[Octavio]

How to know your drone is of the same level as the building?
If you want to fly over a building safely, but you do not know uts height.
How to judge that your drone is higher thanthe building without using obstable avoidance.

I wish when we tilt the camera down slightly the horizon level line should maintain it's pitch so that we know where we are going, don't you think?

 

[NightFlightAlright]

FAA sectional charts will indicate the tallest building(s) for a given area, and also if those buildings have heliports on them, those will indicate elevation.

Otherwise: in most cases you are above the building’s height when the top edge of the wall farthest away from the drone is visible over the wall that is closest.

And a note: when flying over tall buildings, be aware there may be long thin antennas sticking up that can be hard to see on screen. “Peaking” is quite useful here (as it is with power lines).

 

[Dbez1]

FAA sectional charts will indicate the tallest building(s) for a given area, and also if those buildings have heliports on them, those will indicate elevation.

Otherwise: in most cases you are above the building’s height when the top edge of the wall farthest away from the drone is visible over the wall that is closest.

And a note: when flying over tall buildings, be aware there may be long thin antennas sticking up that can be hard to see on screen. “Peaking” is quite useful here (as it is with power lines).

Great information!

 

[Dmcvey]

camera at 0. Rise until you see the far edge of the roof. You will clear it. Same with flying under stuff. Descend until you see the far edge, you will clear it.

 

[Daniel2300]

By visual observation I cannot judge whether my drone is higher that the building.
I had better use obstacle avoidance.

 

[Robert Prior]

By visual observation I cannot judge whether my drone is higher that the building.
I had better use obstacle avoidance.

Assuming your drone has a setting to level the camera, you can. Unless you meant from the ground, which I agree is difficult or impossible.

Many buildings have masts, antennas, pipes, and wires on the roof. I wouldn't trust obstacle avoidance to miss all those.