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Discussion: Do-it-yourself aerial photomapping with drones

in: Orienteering; General

Mar 27, 2020 10:01 PM # 
ebone:
I've been thinking about buying a drone to take photos and videos while I'm out doing fieldwork that I can use to promote the upcoming event, but also to augment my fieldwork capacity while mapping.

While I was online window-shopping, it occurred to me (as it occasionally does) to also check on the state of the technology to see if there are yet consumer-level lidar or photo-based (structure from motion, or SfM) methods available at a reasonable price. To my delight, it seems that there are, at least via WebODM (Open Drone Map), which it seems can generate possibly useful mapping data, including elevation models useful for generating good basemap contours, taking as input anything from high-resolution aerial images to smartphone pics.

Given that lidar data is not available everywhere, and the commercial and DIY lidar solutions seem expensive, I'd really like to develop the capacity to make my own orienteering-precision basemaps, at least of fairly open areas.

Does anyone here have experience doing this, and if you do, can you offer any guidance to a novice wanting to get into this?
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Mar 27, 2020 10:19 PM # 
bbrooke:
I don't have any experience or guidance to offer, but that sounds incredibly cool. Did you see the 2012 movie Prometheus? There were a few scenes with mapping drones. (I can only find the snippet in Spanish and Hindi...)

Mar 27, 2020 11:42 PM # 
Spike:
You might reach out to Klas Karlsson. He's written about drone mapping on his blog and he's got a lot of orienteering experience. His blog is in Swedish, but Google translate might be enough to make sense of it.

His email is here: https://geosupportsystem.se/about/

One of the articles he wrote about open drone mapping:

https://geosupportsystem.wordpress.com/2016/09/07/...
Mar 27, 2020 11:54 PM # 
bmay:
Try contacting jgreen. He's recently moved to Salmon Arm and I believe he has experience in this area.
Mar 28, 2020 3:07 AM # 
gruver:
Chris Forne of AR fame has experience in this.
Mar 28, 2020 3:38 AM # 
robplow:
the new iPad has a lidar sensor - just strap that to a drone.

https://www.apple.com/newsroom/2020/03/apple-unvei...
Mar 28, 2020 6:55 AM # 
ebone:
bbrooke, no, I haven’t seen Prometheus.

Thanks for the tips, Spike, bmay, and gruver.

robplow: “The LiDAR Scanner measures the distance to surrounding objects up to 5 meters away, works both indoors and outdoors, and operates at the photon level at nano-second speeds.”

With a 5-meter range, the iPad’s LiDAR sensor would only be useful for topographic mapping of miniature model landscapes. But the two cameras could probably capture some really nice aerial images if it were strapped to a drone.
Mar 28, 2020 8:25 AM # 
robplow:
really - strapping an ipad to a drone wouldn't work?
Mar 28, 2020 6:41 PM # 
ebone:
really - strapping an ipad to a drone wouldn't work?

Joking aside, I'd bet some engineer somewhere has made it work. (Someone with more time and expertise than I.)
Mar 28, 2020 8:41 PM # 
JLaughlin:
It'd be cheaper to get a lidar sensor designed for drones rather than getting the ipad. It'd also provide better results and cost about the same.

SfM is promising - this is still an active field of research. It relies on the basic principles of photogrammetry but adjusts some of the simplifying assumptions. The results can dramatically vary based on the camera you use. Since you're just trying to get orienteering precision (and not survey precision) results you have a lot of different options as long as you can find a decent piece of software for processing. Just remember, SfM relies on the same principles as photogrammetry with the biggest inherent problem being if you can't see it, you can't map it.
Mar 28, 2020 10:43 PM # 
ebone:
It'd be cheaper to get a lidar sensor designed for drones rather than getting the ipad. It'd also provide better results and cost about the same.

Just to be clear, I'm not considering buying a new iPad for this. My point was that the cameras are probably pretty good, so if one were a geek who already had the iPad and wanted to do it as a lark...

JLaughlin, do you think I should seriously consider DIY lidar? I haven't looked into it, but my fear is that it would not be plug-and-play enough for a non-tech-savvy person like me. I don't want to spend days or weeks of web research to teach myself how to do the post-collection processing. If there is an easy tool or well-documented workflow for this already, then I might be persuaded, because I'm at least okay at following instructions. I haven't done intensive research into the latest lidar options, because I don't want to be an early adopter, preferring to let more tech-savvy folks work out the kinks until there is an easy-to-use solution. I just figured that SfM might have come further because drones with cameras are so inexpensive and prevalent these days.

My immediate interest is to collect data in areas with few or no trees, so the need-to-see-the-ground limitation of SfM would not be a problem.
Mar 29, 2020 1:54 AM # 
Platterpus:
LIDAR sensors for drones are pretty expensive but I think bound to go down. I have no real experience yet but hopefully soon as I have a drone on order.
The 2 mapping programs for drones that seem to dominate are DroneDeploy and Pix4D (Swiss and pricey). These are more for Surveyors and we do not need that kind of precision. Thanks for posting this as most likely Open Source should be good enough for Orienteering Maps.
Mar 29, 2020 11:14 AM # 
JLaughlin:
No, I do not recommend DIY lidar. You may be able to collect the data decently enough but then you'd processing it would be horrendous.

SfM it's a better option (it relies on photogrammetry and those techniques are around a hundred years old) to play with if you have a reliable software package to use. No matter what your plan is still pretty new (drone and off the shelf camera) so there isn't a 'complete, easy package' covering from beginning to end that I'm aware of. Only briefly perusing the software you mentioned, it looks like it has the pieces you'd need. If you are seriously considering this, make sure you understand the documentation and the requirements for the photos (does it need gps positions, how easy is it to take a model and georeference it, etc.) Plus if it doesn't work out great you still have photos to use.

Now, if you ask me this question in a year I probably will have a better answer on set up as I'll get to play with a done with a camera soon soon enough.
Mar 29, 2020 11:12 PM # 
robplow:
https://swiss-o-week.ch/en/news/449-drohnen-en
Mar 31, 2020 12:11 AM # 
moojieturtle:
Ethan did a bunch of mapping from aerial photos with his drone at Lord Hill for the most recent Bog Slog. I'll mention this thread to him but maybe the two of you should connect and he can tell you what he did. :)
Mar 31, 2020 12:51 PM # 
Platterpus:
@moojieturtle.. I would be interested to find out how Ethan did with that too. I have been to Lord Hill and the forest seems very dense. That of course is not from a drone perspective and I am probably just thinking of all that ground clutter.
Mar 31, 2020 1:56 PM # 
gordhun:
Here in Florida one of our mappers got keen on using a drone for mapping then I got keen on having him fly it overhead at one of our events and we could have live streamed shots of the event for the parents and friends to watch back home. The area had a lot of open fields and open pine plantations.
But neither the mapping or the streaming happened. Turns out pretty well every land authority in Florida - state, county parks, forests, preserves and reserves - have prohibitions on drone flights. Something about them running into protected birds and falling on people.
Mar 31, 2020 7:07 PM # 
jjcote:
Birds probably aren't that stupid. Except that there have probably been enough idiots who decided that it was fun to chase birds, and they ruined it for everybody.
Mar 31, 2020 9:08 PM # 
amee:
See also
https://www.swiss-orienteering.ch/files/K%C3%A4rte...

(in German)

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