Any way to calculate necessary altitude to have an area in the camera's field of view?

[Deleted member 94047]

Hello all,

Let's say I want to get a full birds eye view of an area that is best approximated by a circle. Let's say this circle covers a total area of 125,213 square meters. Is there any way to calculate (or even roughly estimate) how high I need to be to have the area in its entirety in the camera's field of view? The camera will be angled at -90°; straight to the ground. I will greatly appreciate any answers.

 

[WithTheBirds]

The answer depends on what drone your flying. Work out the radius of your theoretical circle and what size frame you will need for the circle to fit inside (aspect ratio will make a difference here obviously, M2P is 3:2). Then use basic trigonometry- assuming a right angled triangle where the opposite side is your calculated corner to corner frame dimension /2 and your known angle is 1/2 the FOV of the lens (77deg for a Mavic 2 pro). You are solving the equation to determine the length of the adjacent side which will be the required altitude. It’s going to be significantly above 400ft for any of the Mavics.

 

[Meta4]

Hello all,

Let's say I want to get a full birds eye view of an area that is best approximated by a circle. Let's say this circle covers a total area of 125,213 square meters. Is there any way to calculate (or even roughly estimate) how high I need to be to have the area in its entirety in the camera's field of view? The camera will be angled at -90°; straight to the ground. I will greatly appreciate any answers.

For a single image that can fit a 400 metre circle, assuming you are flying a Mavic 2 pro, you would need to fly 470 metres above your target.
Obviously not practical.
You'd be much better off flying lower and using a mapping app to shoot a number of overlapping images and create an orthophoto.

 

[HawkEye76]

This is easy if the area is visible on a map. Both Litchi Virtual Mission and Dronelink Web App have preview from the drones perspective. Also I think you can set the FOV in Google Earth and set your viewpoint there, then note your elevation.

 

[gnirtS]

Photopills also does it.

 

[Deleted member 94047]

Thanks a bunch guys! This is why I love this forum.

Work out the radius of your theoretical circle and what size frame you will need for the circle to fit inside (aspect ratio will make a difference here obviously, M2P is 3:2). Then use basic trigonometry- assuming a right angled triangle where the opposite side is your calculated corner to corner frame dimension /2 and your known angle is 1/2 the FOV of the lens (77deg for a Mavic 2 pro). You are solving the equation to determine the length of the adjacent side which will be the required altitude.

Brilliant! Will give this a shot.

This is easy if the area is visible on a map. Both Litchi Virtual Mission and Dronelink Web App have preview from the drones perspective. Also I think you can set the FOV in Google Earth and set your viewpoint there, then note your elevation.

I thought about that, but wasn't sure how accurate that would be.

Thanks again all!

 

[johnmeyer]

Plenty of calculators on the web. Just Google "field of view calculator." Examples

Depth of Field (DoF), Angle of View, and Equivalent Lens Calculator

Field of View Calculator

 

[Daniel Lucey]

As says gnertS says ‘Photopills’ is a great way to compose your shot. In ‘Drone View’ Navigate to your site in your map rotate the map and zoom in and out to adjust the drone altitude and composition. You can select your drone model and desired focal length and you are done.

 

[inno]

I bought my first phantom (p3a) in October 2015 and had the same question. not being a trig genius, I used a giant grid marked with lines and numbers which represented distance between them. I flew at an altitude (not exceeding 400') and aligned the grid within my fov (filling my screen). from that I built a spreadsheet to approximate (horse shoes hand grenades) the area covered at a specific altitude. you can find these giant grids almost anywhere (marked with number) when in season. Football that is. highshools are the best on weekends, they are empty. i have done this now with each of my drones. it works. at least for me.

food for thought

Happy and safe flying
inno