Why use a double grid vs a single grid for mapping?

Why should you use a single grid vs a double grid mission?

What advantages for each?

By single grid I mean “Lawn mower” type and double grid Like a “Checkered board”

I don’t understand the difference too much I have tried both and both produced very similar results.
Thanks!

Double Grid: Nothing in the field presents an obstacle to fly this tightly. You have tons of time and batteries to fly like this. This can be really helpful for 3D reconstruction, especially if you’re shooting off-nadir.

Single Grid: Time to get stuff done! Gotta go fast! Also, there might be objects in the field you need to avoid, and you’ve set your transects accordingly. More than sufficient for mapping mostly flat areas.

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It sounds like double grid is for getting detailed 3D models and having the camera angled like -75 degrees then?

And single is best for Orthomoasaics and non detailed 3D models and is best aimed -90 ?

I’m not sure I would be comfortable making “rules” like that. But in general, Double-Grid is when you really want/need a lot of extra detail and coverage.

As for single grid, you should likely still be shooting slightly off-nadir (80-85deg) to help prevent overly-aggressive self-calibration.

Maybe Stephen or someone else can give better guidelines.

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Okay thanks so much for the guidance would the orthomosaic still be looking fine with the gimbal angle 80-85deg?

As long as you are within 5-10 degrees of nadir, your ortho will be fine. It will be better actually, because there will be less in the way of lens calibration issues.

I need to just write a good flight planner. The ideal flight plan can’t be made with any of them.

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I’ve been bugging the creator of Solex to study your flight planning documents. I may have made headway :smiley:

Cool! I may have to revise then…

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Thank you both so much for the help, I look forward to testing this out when it’s not so windy out we got some 35mph gust right now lol

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This is interesting (though I swear that for every n articles I read I get n versions!). I’m going to be flying some bare farmland soon and was considering flying a small section at different heights/angles to get a calibration for each set, but it looks the idea of running a 1/4 section divided into 4 with each 1/4 of the 1/4 flown at alternating offsets of 10 degrees to north, and 2 of them at slightly different heights is very interesting. We are looking to get maps/point clouds to guide some ground truthing on erosion/drainage issues, and this could really help.

There are n versions. The basic principles though are well established: get non-nadir shots to avoid self calibration issues. The rest is just for good 3D reconstructions.

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