Another Mapping Question

Hey there,

i was watching a video from the Youtuber “Visual Joy”.

In one Video he stated that WEBODM would give better results flying one grid with 90degree gimbal and one with 85 degree gimbal with a height diffrence of about 10m. Anyone tried this and gets better results ?

Are there any other Mappping courses / guidelines online avalible that are worth looking deeper into ? Mabe someone has some examples ?

Best

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You need oblique images to get a good camera calibration, if not you might get bowling.

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@APOS80, are you only usin obliwue images (which is as far as i understood 40-45 degree gimbal) or are you using photos with 90 degree and 40-45degree gimbal for the Projects ?

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It depends on what I want to capture. If it’s just ground then maybe about 75-80 degrees and flying in a crosshatch pattern.

I’m learning still but I’ve observed that the more oblique images you got the easier for WebODM to get a good calibration. ORB seems to need more oblique images than Sift/Hahog to get a good calibration.

Hahog has worked the best for me, it’s way faster than sift but much safer than ORB.

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What do you mean by “bowling” ? Best

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The cloud can get a bent shape.

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Hello DvM,

There is a pretty good explanation and example of the “bowl” effect here:

https://www.pix-pro.com/blog/post/bowl-effect

I have experienced it myself, it’s a hazard of processing without GCPs.

Cheers,

Jeff

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Some discussion of it here: Avoiding Bowling over large areas
and see Stephens blog, linked in the first post, which shows a large area with pronounced bowling.

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Rolling Shutter Distortion Correction can also help rectify this distortion over large areas, so all isn’t lost on already collected data that hasn’t had that flag enabled on it yet :slight_smile:

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