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Author Topic: How to handle strong altitude differences on the ground?  (Read 4692 times)

Oli63

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How to handle strong altitude differences on the ground?
« on: June 04, 2012, 04:28:13 PM »
Does anyone have experience with measuring areas with altitude differences of up to 80 meters?
I will have to determine volumes of different heaps in a stone pit (stone quarry), which has lows of 300 m above sea level and highs of 380 meters. Normally we fly in altitudes of 80 m above ground. To get a homogenous and correct mesh, is it better to
a) use a greater overall flying height and take all shots from the same altitude (which resulted in 60-140 m distance to the ground) or
b) could I keep a constant distance to the ground by altering the altitude of the microdrone?

I'd prefer b) as the ground resolution would be better and equal on all photos, but I'm not sure if PS would calculate a wrong 3D model.

Thank you for help.
Oliver
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Wishgranter

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Re: How to handle strong altitude differences on the ground?
« Reply #1 on: June 04, 2012, 06:38:18 PM »
Oli, the most interesant part on Pscan is that can align a lot of things that im personaly not believed that is possible, or unpossible in other solutions. So there wil be no problem with creating a model. but if can test both solution and let us know. im experimenting with resizing of photos 18-11-6Mpix and the Pscan stil can work without problems........
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gEEvEE

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Re: How to handle strong altitude differences on the ground?
« Reply #2 on: June 04, 2012, 08:26:30 PM »
In conventional aerial imaging, rule number one is: always keep the same distance to the ground to minimize scale differences. BTW: you mention a Microdrone: these can be completely programmed in 3D, so you should not have any problems following the topography. However, as Wishgranter said, PS can work with a multitude of scales. Why not fly at 460 m above the complete area and only image the lower zones afterwards? The 460 m imagery makes then your base map and is helpful in aligning the imagery of the lower zones. When you create your DSM and ortho, just disable the 460 m images of the lower zones since you have better footage of these zones.

Geert

Oli63

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Re: How to handle strong altitude differences on the ground?
« Reply #3 on: June 05, 2012, 04:27:53 PM »
Thank you for these arguments.
Yes, I can control the altitude of the drone precisely an assure a constant distance to the ground.
Think I will try both ways but assume, b) will work fine.
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