How Do I Use The Camera to Estimate the Height of an Object?

[AMann]

... and a tough OP. You've gotten a lot of decent suggestions but have rejected them all. I gave you a suggestion of how to center the gimbal and then when I asked what drone you are flying, in order to know if the centering I mentioned could be done on your drone, you never replied.

His drone probably got stuck by the string and is dangling upside down like a kite in a tree from the top of his tower...

 

[MAvic_South_Oz]

I don't know how the height reporting from the drone can have the kind of accuracy he seems to want.

What is the height thing needed for ? Not sure.

If it's just for setting RTH height, then maybe it is accurate enough ?
As long as take off point is regular the tallest tree + say 10m (~30') should be safe.

Is there a command in Go4 or Lichi which centers the camera so that it is pointing straight ahead and parallel to the ground?

I use the directional button (RHS) on controller to bring gimbal either up to straight ahead, or down 90 degrees . . . you push it up from memory, I really don't use it nowadays, and it alternates up level or straight down.

 

[JAW]

... and a tough OP. You've gotten a lot of decent suggestions but have rejected them all. I gave you a suggestion of how to center the gimbal and then when I asked what drone you are flying, in order to know if the centering I mentioned could be done on your drone, you never replied.

Mea Culpa

I apologize if I've seemed unappreciative. I've been using my cell phone (Galaxy S7) which I do not like to use for any sort of typing...my fingers find it impossible to strike less than two keys at a time.
I missed Mr Salty's answer about the slider (post #3) which answered my question and would have basically closed out the thread with his suggestion. johnmyer's suggestion in post #4 led me to look at the manual--on my cellphone--but I could not find the info on assigning a button to the "center" command.

It was never my attempt to be dismissive, This forum is a gold mine of information and makes me, I believe, a better pilot. That's the main reason I chose to fork over a couple bucks each month to upgrade my membership.

When it comes to visually estimating heights, I suck. Hence my original post.

Thanks to all who answered my original post

 

[ToddCarey]

If I am not mistaken, the camera is always straight forward, and horizontal, after the initialization is complete. Just do not touch the tilt of screen, fly up and get close to the highest tree and you should be able to figure out a close estimate of the height.

 

[CJH92474]

You could always use a little trigonometry

To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

Accept third party cookies

Trigga-what?

 

[TN Ray]

Here's the situation----There's a clump of trees in an otherwise open area where I often take off. I would like to know how high the tallest tree is. I could hover at what appears to be the top of the tree by centering its image on the screen and referring to the altitude readout, but unless the camera is pointing straight ahead and (more importantly) parallel to the ground, the readout would not be accurate. Is there a command in Go4 or Lichi which centers the camera so that it is pointing straight ahead and parallel to the ground?
TIA!

I've wondered the same thing! I live in between two hills with lots of large trees. I'd like to be sure my setting for return home is adequate!

 

[Carb63]

???? Visual trig? All you need to do is... ..nevermind. Best you climb to the top and drop a long tape measure down.

LmAo

 

[Canuk]

Using the camera does work .
I have a cell tower on the edge of my town and I wanted to know how high it was . I flew up to it and put the very top light in the middle of my screen . I was about 20’ away from it .
I then looked at my total height. I then pointed the camera down and lowered my bird till the bottom sensor’s picked up the ground . This cell tower was 420’ tall . It has a pile of guide wires around it so I did have to watch where I was going .

 

[PAW]

You could always use a little trigonometry

To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

Accept third party cookies

 

[JAW]

If I am not mistaken, the camera is always straight forward, and horizontal, after the initialization is complete. Just do not touch the tilt of screen, fly up and get close to the highest tree and you should be able to figure out a close estimate of the height.

If that is in fact the case, you have provided the simplest way to determine the height.
Thank you!

 

[joeruby]

Here's the situation----There's a clump of trees in an otherwise open area where I often take off. I would like to know how high the tallest tree is. I could hover at what appears to be the top of the tree by centering its image on the screen and referring to the altitude readout, but unless the camera is pointing straight ahead and (more importantly) parallel to the ground, the readout would not be accurate. Is there a command in Go4 or Lichi which centers the camera so that it is pointing straight ahead and parallel to the ground?
TIA!

If you fly with the Litchi App, there is a big grid X you can turn on and see the exact center of your screen, and then use the button described in post 4 by johnmeyer
works great.

 

[Smalls]

Tie a light string to the drone fly up till camera shows your about level with top of tree. Mark string at bottom, then measure string. That said I understand the question was how do you measure with the camera. Well I used the camera to make sure I was level with top of tree.

 

[azJpp]

Here's the situation----There's a clump of trees in an otherwise open area where I often take off. I would like to know how high the tallest tree is. I could hover at what appears to be the top of the tree by centering its image on the screen and referring to the altitude readout, but unless the camera is pointing straight ahead and (more importantly) parallel to the ground, the readout would not be accurate. Is there a command in Go4 or Lichi which centers the camera so that it is pointing straight ahead and parallel to the ground?
TIA!

Hang a string from the drone. Fly to the top of the tree. Mark the string where it touches the ground. Land the drone. Measure the string.

 

[Oconnb910]

Wow I'm starting to think people have too much time on their hands here!!! LOL

One of the first things I learned when I started flying these drones was to establish you're flying surroundings and get your rth height clicked in and you would just do that by flying straight up camera facing horizon all around and making sure you had a good margin of of that from the tallest object that shows up in the frame. same exact scenario for determining the height of something that you want to measure start on level ground with this, go up until you see the tippy-top of it in your frame and that is your height

 

[Canuk]

Well that just makes it way to easy . You sure you can’t make it harder some how . If not your idea will be rejected. Lol

 

[Samyshine]

Using the camera does work .
I have a cell tower on the edge of my town and I wanted to know how high it was . I flew up to it and put the very top light in the middle of my screen . I was about 20’ away from it .
I then looked at my total height. I then pointed the camera down and lowered my bird till the bottom sensor’s picked up the ground . This cell tower was 420’ tall . It has a pile of guide wires around it so I did have to watch where I was going .

Being that close to cell tower dosent present some interference issues? Serious question as I'm kinda a novice. Only been flying for a six months or so with my mavic and have often wondered how close to a cell tower is too close. And aren't we suppose to cap our flights at 400'. None of my remarks are meant to be flippant or insulting. I'm just curious how the room feels and if there is any data that shows if any interference is present when near towers. Thanks

 

[BrucenYvette]

Follow instructions below, then measure...Don't forget to add stump height for accuracy!

 

[Alan O]

What drone are you flying?

 

[tribar]

Having some difficulty locating that option. I'm running Android on a CrystalSky

 

[Earthman]

View attachment 74730

Theodolite Augmented Reality Viewfinder for iPhone and iPad

I also use Theodolite on my iPhone (the Op is using Android, so he’s out of luck) to measure the vertical angle. I also use the map feature in Theodolite to estimate horizontal distance. I then plug both numbers into a small spreadsheet on my phone to do the trig for height. Since the sensors in the iPhone need calibrated to improve Theodolite’s accuracy, I designed and 3D printed an artificial horizon to facilitate the calibration. This setup works great.