Height to Photo 1 Acre?

[Fleetwood250]

Does anyone have or know a formula to figure how high we wold have to fly in order to photograph 1 acre of land? What about 10 Acres or 50 acres? I live in a rural area and have been asked to photograph some farmland, all in one shot.

I was just wondering if there is a way to figure how high I would have to fly in order to photograph a certain size piece of land?

I realize of course that it would depend on the shape of the property. For the sake of making this easier, let's pretend the farm is square.

If I was asked to photograph a 50 acre farm, how high would I have to be?

Thanks in advance for your help.

 

[MotorCycle-Man]

Might be better to ask a pilot friend to do it for you..Buy him some gas and take a good high quality Digital camera along and shoot away
be sure it a clear skys day...and have him make several passes full length...same way each pass.

. Then also you could use the drone and take several pictures and piece the pictures together in photo shop....I've done that !

max altitude for us here in the States is 400 feet.
FAA regulations say drones shouldn't be flown above 400 feet. Higher than that, drones start to interfere with the national airspace. They can't be flown within a few miles of an airport, and they can be used only for fun — not for commercial purposes.

 

[natnatroswell22]

Does anyone have or know a formula to figure how high we wold have to fly in order to photograph 1 acre of land?

It actually depends on what drone you use.

 

[Fleetwood250]

Might be better to ask a pilot friend to do it for you..Buy him some gas and take a good high quality Digital camera along and shoot away
be sure it a clear skys day...and have him make several passes full length...same way each pass.

. Then also you could use the drone and take several pictures and piece the pictures together in photo shop....I've done that !

max altitude for us here in the States is 400 feet.
FAA regulations say drones shouldn't be flown above 400 feet. Higher than that, drones start to interfere with the national airspace. They can't be flown within a few miles of an airport, and they can be used only for fun — not for commercial purposes.

Yes, I am aware of the max height. That is why I was asking if anyone had a formula to help figure the height so I would be able to calculate how high I would need to go in order to capture a particular size piece of property. I have my Part 107 license, and am getting requests to do shots of various properties in the area.

I have thought about getting a pilot buddy to take me up in his plane. I have a photography business and could use one of my high end DSLRs. Just thought it would be less expensive to use my drone.

Thanks!

 

[Fleetwood250]

It actually depends on what drone you use.

Good Point. I am current flying a Phantom 4 Pro 2.0

 

[MotorCycle-Man]

After i shut down last night...i thought of why don't he just go to Google earth and zoom in on the property...and save it to the computer....However Now i see your qualifications and also the part 107 FAA licence you have and i fully do understand what you really want to do and accomplish...The best of luck to you and hope that you get some great answers ! last night when i read your question...i merely thought you were a droner with a question !

 

[umanbean]

If I was asked to photograph a 50 acre farm, how high would I have to be?

Higher than you can legally fly in the United States and most 1st world countries.

I won't even pretend to be qualified to school you on this subject, but will point you in the right direction - your best bet is to use a flight app specifically designed for mapping. You designate the area, the overlap, etc. The bird flies the mission autonomously, takes lots of pictures, then you stitch them all together into one image.

Try surfing around in the Surveying and Mapping subform here.

 

[Oso]

Does anyone have or know a formula to figure how high we wold have to fly in order to photograph 1 acre of land? What about 10 Acres or 50 acres? I live in a rural area and have been asked to photograph some farmland, all in one shot.

I was just wondering if there is a way to figure how high I would have to fly in order to photograph a certain size piece of land?

I realize of course that it would depend on the shape of the property. For the sake of making this easier, let's pretend the farm is square.

If I was asked to photograph a 50 acre farm, how high would I have to be?

Thanks in advance for your help.

I don't have experience with this personally, but I do recall a very rough rule of thumb from this site. 175 feet for 1 acre, 400 feet for 8 acres. This depends on the drone since they have different FOVs. Most say that it's better to fly lower and take more high resolution photos and then stitch them together with something like Drone Deploy.

Again, I have no personal experience with this so please research this more. I may be off base with my recollection, and I would defer 100% to anything said by @Meta4 on this topic.

 

[Tom45]

You can do a test with your drone to determine the field of view vs. distance. Set the drone on a flat surface and aim the camera at something like a brick wall. Then take a photo of the wall, and note the distance from camera to the wall.

Look at the resulting photo and count bricks (or whatever) to determine the width and height of the field of view. Divide those numbers by the standoff distance and you will have image height per foot of standoff and image width per foot of standoff.

I think you will find that you don't have to fly very high to get quite a few acres in a single image looking straight down. If you can photograph at something other than 90 degrees straight down the field of view becomes very large.

Finally, you can point the camera straight down and fly the property while taking a video. Microsoft's free Image Composite Editor (ICE) can stitch still images or videos.

The attached image shows a 3 acre vineyard in the foreground. While not pointed straight down, my P4P could have easily covered the 3 acres from a legal height. With the angle there is probably well more than 50 acres in view overall.

 

[drvrbobob]

It actually depends on what drone you use.

I am curious, care to explain in more detail?

 

[BigAl07]

I am curious, care to explain in more detail?

Different drones use different cameras which have a different FOV. It gets more confusing when you add drones that have different camera payloads (Inspire) and even more when you factor in cameras that can use different lenses.

 

[Fleetwood250]

Higher than you can legally fly in the United States and most 1st world countries.

I won't even pretend to be qualified to school you on this subject, but will point you in the right direction - your best bet is to use a flight app specifically designed for mapping. You designate the area, the overlap, etc. The bird flies the mission autonomously, takes lots of pictures, then you stitch them all together into one image.

Try surfing around in the Surveying and Mapping subform here.

Thanks for the reply and the info.

 

[Fleetwood250]

You can do a test with your drone to determine the field of view vs. distance. Set the drone on a flat surface and aim the camera at something like a brick wall. Then take a photo of the wall, and note the distance from camera to the wall.

Look at the resulting photo and count bricks (or whatever) to determine the width and height of the field of view. Divide those numbers by the standoff distance and you will have image height per foot of standoff and image width per foot of standoff.

I think you will find that you don't have to fly very high to get quite a few acres in a single image looking straight down. If you can photograph at something other than 90 degrees straight down the field of view becomes very large.

Finally, you can point the camera straight down and fly the property while taking a video. Microsoft's free Image Composite Editor (ICE) can stitch still images or videos.

The attached image shows a 3 acre vineyard in the foreground. While not pointed straight down, my P4P could have easily covered the 3 acres from a legal height. With the angle there is probably well more than 50 acres in view overall.

Thanks! I appreciate your input.

 

[drvrbobob]

Different drones use different cameras which have a different FOV. It gets more confusing when you add drones that have different camera payloads (Inspire) and even more when you factor in cameras that can use different lenses.

That makes sense, never thought of it that way. Thanks.

 

[Meta4]

Does anyone have or know a formula to figure how high we wold have to fly in order to photograph 1 acre of land? What about 10 Acres or 50 acres? I live in a rural area and have been asked to photograph some farmland, all in one shot.

Here are some numbers to give you a guide.
Assuming you flew a Phantom 4 pro and shot in 3:2 (other aspect ratios would capture a smaller area)
Altitude = 200 ft Area covered = 300 x 200 ft = 1.4 acres
Altitude = 400 ft Area covered = 600 x 400 ft = 5.5 acres
Altitude = 1200 ft Area covered = 1800 x 1200 ft = 49.6 acres

An acre is easy but you can see the problem with larger areas.
For big areas, the thing to do is to fly a grid, shooting a lot of precisely overlapping images and stitch them in a mapping program (a photo program won't make an accurate map necessarily).
The advantage of this is you get a huge composite image with tons of detail and you don't have to fly at crazy heights.
Here's an example of a 12 acre site I mapped from about 50 individual images.

 

[sar104]

Does anyone have or know a formula to figure how high we wold have to fly in order to photograph 1 acre of land? What about 10 Acres or 50 acres? I live in a rural area and have been asked to photograph some farmland, all in one shot.

I was just wondering if there is a way to figure how high I would have to fly in order to photograph a certain size piece of land?

I realize of course that it would depend on the shape of the property. For the sake of making this easier, let's pretend the farm is square.

If I was asked to photograph a 50 acre farm, how high would I have to be?

Thanks in advance for your help.

For a 4:3 ratio image from a camera with a diagonal field of view, Ø, the area, A, imaged from a height h is given by:

A = (24/25).h².tan²(Ø/2)​

If h is in feet then A is in square feet. In acres:

Acres = A/43560​

Ø is approximately 90° for a Phantom.

 

[Fleetwood250]

Here are some numbers to give you a guide.
Assuming you flew a Phantom 4 pro and shot in 3:2 (other aspect ratios would capture a smaller area)
Altitude = 200 ft Area covered = 300 x 200 ft = 1.4 acres
Altitude = 400 ft Area covered = 600 x 400 ft = 5.5 acres
Altitude = 1200 ft Area covered = 1800 x 1200 ft = 49.6 acres

An acre is easy but you can see the problem with larger areas.
For big areas, the thing to do is to fly a grid, shooting a lot of precisely overlapping images and stitch them in a mapping program (a photo program won't make an accurate map necessarily).
The advantage of this is you get a huge composite image with tons of detail and you don't have to fly at crazy heights.
Here's an example of a 12 acre site I mapped from about 50 individual images.

Thank you Very Much for the detailed reply.

 

[Fleetwood250]

For a 4:3 ratio image from a camera with a diagonal field of view, Ø, the area, A, imaged from a height h is given by:

A = (24/25).h².tan²(Ø/2)​

If h is in feet then A is in square feet. In acres:

Acres = A/43560​

Ø is approximately 90° for a Phantom.

Nice! Thanks!

 

[y2khardtop]

from experience, 50 acres is easy at 400' with my P3P. Larger properties must be shot further away or as Panos. I have several hundred acres of land, and often shoot automotive race tracks, and wish we could go higher.

 

[Meta4]

Thank you Very Much for the detailed reply.

I was assuming you meant topdown photos and the information was for those.
If you shot obliques as in post #19, there's no ideal altitude that could be calculated.