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Map processes if done in parts but not as a single map

I've just processed a map, and about a third of the area is missing.

The overlap view shows the missing area as red dots, ie photos with no overlap.  This is despite running 80% overlap at 120m.

When I test a small free map with just the missing area though, it comes through nicely.

Could this be just because I left autotrim on, on the larger map?

Original job

https://www.mapsmadeeasy.com/maps/public/fe799fb8b4354474b5b3bd0095999508

Test on missing area

https://www.mapsmadeeasy.com/maps/public/2bc11bac8c084796848922228fb1d860

Michael Dufty

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The issue here looks like the variable lighting. If the lighting changes between two pictures that is essentially the same things as motion to our system. The features in the two images look different so the features don't match. You can usually overcome this with lots of overlap. 80% is the minimum for structured plants like this. More overlap may help. The Mavic needs more than most because it doesn't really do a great job with greens.

Some of your source images look pretty blurry too. Make sure your data collection app isn't letting you out run the light that is available. 

It also looks like it was windy at the time of your collection so all the little moving branches and leaves make it almost impossible to match features. 

It is not possible to run a map with different options without uploading the imagery again. 

Zane
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Related question, is it possible to re-run a map with autotrim off, or do I need to re-upload all the images?

Michael Dufty 0 votes
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Shouldn't issues like blurry images and light changes have the same effect regardless of how many photos are stitched.  The area missed from the first map worked fine when I processed it separately.  Including linking to images in the other map.   Do I need to limit the number of photos in a map?

Michael Dufty 0 votes
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If a shaded area is processed as one map then the images won't be super different. The issue comes when clouds move across the area during the time of collection which will make any area in which there was a change in lighting potentially problematic. 

Zane 0 votes
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Still doesn't make any sense to me, as the small area includes all the missing images, and images that were matched.  I believe the photos were all taken within 15 minutes of each other on a cloudless day.

Michael Dufty 0 votes
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After looking more closely at your input images you have a bunch of different things going on here. It appears the images at the ends of your paths are taken while that camera is rotating. This makes the end images pretty heavily distorted, especially because of the Mavic's slow rolling shutter. 

Also, you have what we refer to as a travelling sun spot in your images. This explains why it looked like some areas were darker than others. When the sun is near solar noon you actually get a shadow of the aircraft in the images and a strong bright area in every image that gets taken. This is bad because the features look different in every picture since the lighting changes. 

You can see the strong sunspot along the middle of the right side. 

You can read other threads about that here:

https://support.dronesmadeeasy.com/hc/en-us/community/posts/214857143-Flat-3D-model-

https://support.dronesmadeeasy.com/hc/en-us/community/posts/209993603-Incomplete-Map

 

Zane 0 votes
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Thanks, interesting about the sunspot, I often notice it when I'm paragliding, but hadn't thought about it in relation to the drone.

It still doesn't explain why the photos have good matches when I process in smaller groups, and not when I do all at once.  Is it maybe dependent on the order the photos are processed?

Michael Dufty 0 votes
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