I was wondering what an easy formula to calculate the dimensions of the ground covered by an aerial photograph.

I know the following:

  • camera sensor size (mm x mm)
  • camera focal length (mm)
  • height above ground (m)

How can I combine these variables to calculate metres by metres covered by each individual image captured?

Thanks, Jarrett

  • Im not really a very knowledgeable about the subject, but according to the wikipedia's arcticle about the Angle of view it is possible to calculate the FOV using only your parameters and then by applying basic trigonometry functions to derive the footprint? Ofc it is just an estimation because there are lens distortions that needs to be taken into account if you want to be super precise. – nickves Oct 24 '13 at 20:30

So if I assume the following variables:

x = camera sensor x size

y = camera sensor y size

f = focal length

h = height above ground 

And I am looking for:

ay = photo y ground distance

ax = photo x ground distance

Would these formulas work? making sure that I compare the proper units to the proper units.

(h/f)*x = ax

(h/f)*y = ay

Does this make sense. See my crude photo below (source of diagrams:http://www.nrcan.gc.ca/earth-sciences/products-services/satellite-photography-imagery/aerial-photos/about-aerial-photography/891)

enter image description here

  • J-roc, did you ever get a definitive answer to this? bergmanphotographic.com/bpsweb/index.php/home/tips/… has some detail similar. Am needing to go down this route myself, but also factoring in camera tilt, so would like to stand on your shoulders if you've already figured out this part :) – BlinkyBill Apr 29 '14 at 22:18
  • i just changed the formula i had some variables backwards. thanks Cherry_UW! i was trying to use my formula from this post last week and it didn't make sense good catch. formulas are not something that gets voted on being right or wrong, they either are correct or are incorrect regardless of peoples opinion. – gomapping Feb 10 '17 at 23:33

We have created an webpage with a script that will perform the calculation for you: Aerial Camera Ground Footprint Calculator. You just have to enter the variables mentioned and click the Calculate button. Please note the calculator interface is in English, but the primary site language and explanations are in Spanish.


Esta app posee un UAV Photo Coverage Calculator: http://playboard.me/android/apps/com.xdrones.dronestoolsupdate1?lang=en&ref_host=www.xdrones.es

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