Mapping

[Kyklopes]

All I have available is a Mini 2 and I need to create a map of 40 acres. Because there isn't SDK support I'll have to do this manually. Any suggestions on how much overlap I should have for each picture? Software I should use to stitch them together? Any other tips that will help me succeed? Thank you.

 

[Gagey52]

I tried to manually fly a pattern over a stockpile and used WEBobm to stitch them together. Wasn’t accurate enough to get a good volumetric assessment but was able to use the ortho in a report. 40 acres will certainly test your metal as a pilot to fly a good pattern. What are you using the results for?
Regards

 

[Meta4]

All I have available is a Mini 2 and I need to create a map of 40 acres. Because there isn't SDK support I'll have to do this manually. Any suggestions on how much overlap I should have for each picture? Software I should use to stitch them together? Any other tips that will help me succeed? Thank you.

You could possibly manage 5 acres manually (at a pinch).
But I wouldn't waste my time trying to do 40 acres.
You need to use an app to automate the process to achieve complete coverage with overlaps of about 70%.
Can you borrow a suitable drone maybe?

Recommended and Supported Drones

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Download the DroneDeploy app to plan and fly the mission and you can use their free trial to have them do the processing.

Here's an example of the mission planning for a 40 acre site:
Note the number of images required

And here's an example of the photos captured in a smaller mapping mission .. about 15 acres.
You cannot do this manually, it's very had to stay on course and impossible to manage overlaps.

 

[Gagey52]

It’s a shame they (drone deploy) haven’t included the Mavic mini2. A great little aircraft.
Regards

 

[Kyklopes]

And here's an example of the photos captured in a smaller mapping mission .. about 15 acres.
You cannot do this manually, it's very had to stay on course and impossible to manage overlaps.

What do the blue rectangle in the picture represent?

 

[Meta4]

What do the blue rectangle in the picture represent?

Each one is the centre of an individual photograph taken during a mapping mission

 

[Kyklopes]

Thank you. I will give the manual method a test on a smaller section. I find that forgetting to reset the gimbal to 90 degrees, after it snaps to 80 degrees when I move to the new location, has been the biggest issue in past attempts.

 

[surfbird]

Hi,
Hope you can help me with some info here.
I'm working on an app targeting the mini2 only. It seems like many wants to do this mapping kind of thing, which I never done, so please help me out
Is there any software that can plan the waypoints, decide where to take the photos and export that into some readable format, like csv.
I run the csv in my app and take the photos where they supposed to be taken and then I can feed back all photos back to the same? software and it merges all the photos correctly.

So what I want is
1 start and endpoint gps loc for each flyover
2 gps points where to take each photo.
3 Do I need to stop the drone to a complete standstill when taking each photo, or can it be moving at full speed?
4 Is the gps data embedded in the photos enough to merge them, or is there any additional data they needs to be tagged with?
5 Should the photos be raw or jpg?
6 Any specific camera settings? Like locked shutter and iso speed o r fully automatic?
7 Would it help to have the gimbal in free mode? Filming gets a lot steadier with this.

Please let me know if you know anything about this. It would save me a lot of time, I can spend some time on the app instead.

Thanks!

 

[Meta4]

Hi,
Hope you can help me with some info here.
I'm working on an app targeting the mini2 only.

So you are trying to reinvent the wheel and create DroneDeploy for the Mini 2 without an SDK which would allow your app to access the features of the drone?
There's a lot more to it than you imagine.
Good luck with that.

 

[surfbird]

So you are trying to reinvent the wheel and create DroneDeploy for the Mini 2 without an SDK which would allow your app to access the features of the drone?
There's a lot more to it than you imagine.
Good luck with that.

I think you don't understand what I'm asking,


The workflow is:
1 Generate the mission from an existing software.
Output should be: 1 Waypoints to fly
2 Where to take the photos.

2 Run the mission in the app. The app produces output photos

3 Feed the photos to any existing software that can merge the photos.

I'm asking if there is any existing software that can do point 1 and 3.

The app will only do the mission and take the photos. Nothing more.
The app is a walk in the park as I see it, I'm almost there. But you say it's complicated? Am I missing something here.
I've already made an pretty neat followme mission, that works really well, so all functionality is in place, thats was the hard part to get it to work on a mini2.

I would be really helpfull if you can point me to any software that can do 1 and 3 above.

Thanks

 

[Meta4]

I think you don't understand what I'm asking,

I think I did .. and I also understand what's involved in drone mapping, having done plenty of it.

I'm asking if there is any existing software that can do point 1 and 3.

1. Download DroneDeploy and look at what it does/how it does it.
Yours will have to be able to calculate where to take each photo from to achieve 70% overlaps at various altitudes.
This will generate lots of photos.
There's no need to stop to capture the images, if you did, it would take forever.

3. Agisoft Metashape

 

[surfbird]

I think I did .. and I also understand what's involved in drone mapping, having done plenty of it.

1. Download DroneDeploy and look at what it does/how it does it.
Yours will have to be able to calculate where to take each photo from to achieve 70% overlaps at various altitudes.
This will generate lots of photos.
There's no need to stop to capture the images, if you did, it would take forever.

3. Agisoft Metashape

Thanks, I will check these out.

 

[011111110]

I think you don't understand what I'm asking,


The workflow is:
1 Generate the mission from an existing software.
Output should be: 1 Waypoints to fly
2 Where to take the photos.

2 Run the mission in the app. The app produces output photos

3 Feed the photos to any existing software that can merge the photos.

I'm asking if there is any existing software that can do point 1 and 3.

The app will only do the mission and take the photos. Nothing more.
The app is a walk in the park as I see it, I'm almost there. But you say it's complicated? Am I missing something here.
I've already made an pretty neat followme mission, that works really well, so all functionality is in place, thats was the hard part to get it to work on a mini2.

I would be really helpfull if you can point me to any software that can do 1 and 3 above.

Thanks

Given the lens field of view, you should be able to calculate the coverage area for any altitude using simple trigonometry. Once you know that, you can calculate where you need to go for the first photo, and each one after that based on your grid pattern and overlap requirements. The math shouldn't be that hard (though admittedly I've never tried it). It only gets complicated if you're dealing with really huge areas where the non-parallelism of longitude lines becomes an issue, but our drones can't fly far enough for that to be a problem

 

[surfbird]

Given the lens field of view, you should be able to calculate the coverage area for any altitude using simple trigonometry. Once you know that, you can calculate where you need to go for the first photo, and each one after that based on your grid pattern and overlap requirements. The math shouldn't be that hard (though admittedly I've never tried it). It only gets complicated if you're dealing with really huge areas where the non-parallelism of longitude lines becomes an issue, but our drones can't fly far enough for that to be a problem.

Thanks, I was hoping not having to do that. I would like to do a proof of concept first, with so little effort as possible.

Do you know if the orientation of the photos matter? Should they all be taken with the same yaw with the drone or can the drone be randomly rotated?

 

[011111110]

Thanks, I was hoping not having to do that. I would like to do a proof of concept first, with so little effort as possible.

Do you know if the orientation of the photos matter? Should they all be taken with the same yaw with the drone or can the drone be randomly rotated?

I guess that depends on what you're using to stitch them together, but you can always rotate them in software by calculating a transform matrix from the yaw angle. For all practical purposes, you'd be taking the photos in a rectangular grid pattern anyway, so each photo would only need either a 0 or 180 degree rotation applied.

 

[surfbird]

I think I did .. and I also understand what's involved in drone mapping, having done plenty of it.

1. Download DroneDeploy and look at what it does/how it does it.
Yours will have to be able to calculate where to take each photo from to achieve 70% overlaps at various altitudes.
This will generate lots of photos.
There's no need to stop to capture the images, if you did, it would take forever.

3. Agisoft Metashape

Now I tried dronedeploy. My first mapping ever . Cool software, could even import it to blender .
Used my old mavic 2

I got a few more questions:
1 It flew quite slow, no way near the max speed. Why is that? To get sharp photos?
2 It pointed the gimbal a little bit forward. Is that the best way, ot should it point straight down?
3 Dronedeploy made a nice model, but when i try to merge the photos in Agisoft Metashape it didn't cope well. Only like 10% got a match.

Anyway, I got the mini2 to continously take 1photo per second programmaticly, couldn't go faster than that. I don't know if thats a limiting factor or not.

So now the only thing left is to have it fly in straight lines over an area. Hope I can do some test missions over the weekend. I'm a little unsure whats best to do with the gimbal. Should it be set to lock when taking photos or not.

 

[Meta4]

1 It flew quite slow, no way near the max speed. Why is that? To get sharp photos?

Perhaps you were flying too low?
It's not necessary to fly slowly to get sharp photos if lighting is good and you are flying high enough.
Here's an example of a typical speed for a mapping mission.

2 It pointed the gimbal a little bit forward. Is that the best way, ot should it point straight down?

Shooting straight down is what's usually done

3 Dronedeploy made a nice model, but when i try to merge the photos in Agisoft Metashape it didn't cope well. Only like 10% got a match.

Hard to say without not knowing what was involved.
But some ground surfaces are more difficult (like forest canopy).
If you fly too low, there is too much difference between adjacent images and flying higher helps.
Increasing the overlap can also help.

Anyway, I got the mini2 to continously take 1photo per second programmaticly, couldn't go faster than that. I don't know if thats a limiting factor or not.

Shooting on a time interval isn't going to get proper overlaps

 

[surfbird]

I got a positiv cov-test so I got some time over to try my mini2 today.
Meta4 I understand what you mean with "There's a lot more to it than you imagine." The 3d model looks like *****.
I hope I can fix it with better flight planning, I noticed droneplanner circles round the mapping area in the end. It might help?

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I never got good result with Metashape.
I tried open drone map or something. Worked better, but took almost an hour to process all photos.:-/

I've got a problem with the drone not flying in straight lines. Have you seen anything lika that?
It was very windy (10m/s cross). It flies straight in sim. I wonder if it's the wind or the compass not aligned with the gps course? I'm using virtualstick, since no waypoints is supported in mini2. Have a trick up my sleeve though.

Please Meta4, let me know what you think can be improved, this is new territory for me.
Your input is very valuable (and others of couse)

Thanks

 

[Meta4]

The 3d model looks like *****.
I hope I can fix it with better flight planning, I noticed droneplanner circles round the mapping area in the end. It might help?

3D modelling is different from mapping.
With mapping, all you care about is the lookdown view.
But to deal with vertical surfaces you need additional oblique imagery to be able to give details of those surfaces not properly visible in vertical shots.
DD used to have the circle thing, but I notice it's not in the current version?

I never got good result with Metashape.

Metashape is the industry standard.
The issue would be that you just didn't capture good details of what you were interested in.

but took almost an hour to process all photos

There's a tremendous amount of processing in photogrammetry with teh software identifying and matching hundreds of identical points in overlapping photos.
It's easy to have a few hours processing with big projects.

I've got a problem with the drone not flying in straight lines. Have you seen anything lika that?
It was very windy (10m/s cross). It flies straight in sim. I wonder if it's the wind or the compass not aligned with the gps course?

I've never had that issue in DD.
If strong enough, the wind could make the lines a little wiggly but if the drone normally hovers in place, there's no compass problem.

 

[surfbird]

3D modelling is different from mapping.
With mapping, all you care about is the lookdown view.
But to deal with vertical surfaces you need additional oblique imagery to be able to give details of those surfaces not properly visible in vertical shots.
DD used to have the circle thing, but I notice it's not in the current version?

Metashape is the industry standard.
The issue would be that you just didn't capture good details of what you were interested in.

There's a tremendous amount of processing in photogrammetry with teh software identifying and matching hundreds of identical points in overlapping photos.
It's easy to have a few hours processing with big projects.

I've never had that issue in DD.
If strong enough, the wind could make the lines a little wiggly but if the drone normally hovers in place, there's no compass problem.

Ok thanks.

The problem was the virtualstick mode. I had to implement an crosstrack pid-regulator. Now it goes steady . You can clearly see where the pid-regulator starts swinging in at each turn. I havn't adjusted it correctly.

What do you think, will this do for mapping, if I get rid of the s-turns?

Would it be a good idea to turn the gimbal sideways to cover more area, like left, down, right, forward. Or is it a bad idea?