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3D data flattening - 80% overlap

Hi Maps Made Easy,

My most recent maps "Kelley Point" and "Kelley Point 2" appear to have relative elevations that are too low.  At first glance after uploading to sketchfab, the vegetation generally appears much too short - the shadows cast on the water are a good indication that the surrounding trees aren't rendered tall enough to cast that long of a shadow (at 3pm, in Portland OR, on 8/23).

I don't have any ground truth data to prove just how far off the Z heights are.  Anecdotally, viewing the point cloud in Quick Terrain reader, and scaling the Z heights makes it appear to be off by about a factor of 4 or 5.

Besides including some water in this mission, I've otherwise followed all of the guidelines.  Disclaimer: "Kelley Point" was processed with color-corrected images exported from Lightroom.  However, "Kelley Point 2" was processed using jpgs straight from the P3P.  Both models have the same flattened appearance to me.  Overlap report looks generally quite good from my experience.

Can you please comment or advise? 

Thank you,

-Nick Wagner

 

N Wagner124

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The area that you covered was pretty small and had a lot of reflective surfaces in it. That, combined with the trees made it pretty hard for the system to get things reconstructed. The color correction wasn't the issue. 

Zane
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Hi Zane,

Thanks for the analysis. 

How do you recommend I fix this?  I want to be able to model small streams and rivers like this, and I have in the past with better success.

Do you recommend: 1) Higher overlap %, 2) Mapping a larger area, 3) Flying at a higher altitude to reduce the amount of water in each frame, 4) something else?

 

Thank you,

-Nick

N Wagner124 0 votes
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Modeling rivers is going to be hard since they do not work well with our Data Collection guidelines. People do it but you need a lot of overlap to make up for the motion and reflections. 

Just mapping the small skinny area of the river is going to be problematic. Include some more area along the sides to give our system some solid stuff to be able to anchor to. 

Zane 0 votes
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