AGL reading

I have not seen any information on what is actually being recorded on the Y axis (elevation) If we are talking about a DJI P4P camera, which has a 20 megapixel sensor, is the height being recorded by the center pixel in the picture? Since it cant be all pixels.

Additionally, speaking as a professional photographer, what relationship is there in shutter speed and speed of the horizontal movement over a landscape. I know from experience, in photography, around 1/1000th of a second is needed to stop motion blur when panning across a scene. And even with a $8,000.00 full frame camera, I normally set my own relationships with shutter speed, aperture, and ISO. Keeping things in auto mode, with hundreds of photos taken, is only an open door to variances in exposure, especially not knowing how the DJI or any camera for that matter adjusts exposure by being shutter priority, aperture priority or auto ISO. I see nothing in any webinar about the camera. lets not forget, one major component in all of this science and technology, is being a good photographer and having an understanding of how to create what your trying to create.
Keith Provost

Hi @KeithProvost,

Thanks for swinging by the DroneDeploy Forum. To answer your question, the elevation or Z values are recorded in every image, rather than every pixel. DJI drones usually record the altitude in the EXIF data of the images and DroneDeploy uses that information to do some advanced math to figure out the elevation of your maps by looking at differences in perspective between two or more overlapping images.

As for the shutter speed question, DJI shutter speed is usually fast enough to maintain consistent exposure and avoid blurriness. Please note that while capturing the images with DroneDeploy app, you can set Exposure and Focus manually using the DJI GO app. That way, you could then choose the setting that better works for your need. Other photographers in the forum might contribute to a better understanding of this :slight_smile:

Have a wonderful day!


Hi Andrea,
Your answer to the first question really doesn’t answer it. In any given picture taken you have 20 million different pixels recorded. What pixel is associated with the gps reading? All of the can’t.

It is my belief, without doing any testing to prove it, that a shutter priority exposure setting will render the best results.
And to make things even better in situations where there are large differences in AGL in a given map, locking down shutter speed and aperture, and using an automated ISO would be better. A large aperture of 2.8 renders a short field of focus, an aperture of around 11 would be perfect in these situations.

The GPS value is associated with the image as a whole and is only the correlation of where the drone is. The algorithm locates common points in each photo and depending upon it’s location in each photo has a 3D point created for it. Trigonometry 101.
As for the camera settings you are correct that being a good photographer is a huge part of obtaining good images and thus good accuracies. There are several threads in the forum that discuss ideal conditions. The most ideal condition is full overcast which will minimize highlights and shadows. Shutter at 1/240 to 400, ISO 200-400 and F4-6 are pretty standard numbers for the P4P. Remember you are at 200ft+ AGL so it’s not like shooting a football game with a 400mm lens, there’s allot more available light.

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