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Drone work
Posted by ridge on April 14, 2019 at 2:25 amGoing to do my first drone projects. Not my drone but an associate’s. Both of us sort of new to it. Will be processed by DroneDepoy.
First project is a gravel county road just over a mile long. Need to do new road design, utility planning, etc. Thinking maybe fly about 200 feet high. What spacing should control targets be placed? Planning on using 12 inch diameter, white plastic bucket lids to mark control points/panels. Would stake them down with a 3/8 inch spike and 2 inch diameter fender washer painted black in center of lid. Is this good enough to mark the control point? Each will be shot with a long RTK shot, at least two times.
Second site is about a 20 acre reservoir site. Need contours. What control point spacing would work here?
Third site is a 5 acre future industrial lot.
Fourth site is a twenty acre subdivision being planned.
Any hints, recommendations would be helpful, such as how high to fly and control point spacing.
ridge replied 5 years, 5 months ago 9 Members · 26 Replies -
26 Replies
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Do surveyors have a rule like engineers not to practice in areas you are not competent?
Before I offered any drones services, I have a handful of “practice” site completed so I knew the process before offering the service.
Just curious.
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Some missing info… if you are using typical p4p, I would drop the height to around 120. Don’t allow gaps in a 900 to 1000′ complete overlap target to target. On the corridor portion I do targets left side, both sides, right side, both sides, etc., starting and ending with doubles. That will take about an gour longer on this job that the standard 1000′ left, right, left. It will tighten your work up and avoid return trips.
For targets i paint a checkerboard of blue and white using a large piece of cardboard for a template. 60d nail or mag hub in the center and i now have site control for construction. I always fly well beyond the required corridor so my control survives. It keeps the distortion on the published surface low and provides a context ortho for nearby design considerations. Again, the added time and expense is extremely cheap insurance…
Good luck.
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In a way these will be practice projects as they are for me. I’ll need to do them over if I don’t get it right, no client is going to be billed. I’m asking questions for help if I can get it from some experienced operators on this forum.
As far as engineers or surveyors I have both licenses so once I gain the proper experience maybe it will apply to both. You got to start somewhere.
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I’d suggest reading the fine print at Drone Deploy. Last I read, they reserve the right to redistribute your photos. My clients would not appreciate that.
Lots of other things to consider.
After some trial and lot’s of errors, you will get it figured out. To prevent error you may want to consult someone with more experience.
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OK, can fly at 120. Will need to do in several sections as the elevation gains about 200 feet from one end of road to the other. probably set panels about every 660 feet and at the 40 lines both sides maybe a hundred feet out from the right of way, doubles at both ends. the road generally goes westerly. I think this drone has a 12Mpixel camera.
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I don’t care if they redistribute the photos, I’m the client.
I have TBC but not the photogrametry module. If this looks more promising I’ll look into it.
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A drone with only 12mp camera is likely not to have a 1″ sensor, and a mechanical shutter. The P4Pro and P4Pro 2.0 have a 20mp camera with a mechanical shutter.
The free 30 day trial of Drone Deploy does not accept Ground Control points.
Looks like you may be on track for failure.
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The Trimble software is free. Worth every penny…
Lee has a point. Many services require 20mp minimum (among other specs). 12mp sounds like a P3. Still a good bird but it is more limited.
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Your suggestion of “white plastic bucket lids to mark control points/panels” do not work well. Difficult to find the center and too much reflective surface in bright sun light.
These 24″ aerial targets work great and last for many flights.
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The drone is a DJI Mavic pro platinum.
Not using 30 day trial of Drone Deploy. Associate has regular account.
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I planned to drill hole in lid center and place a 2 inch diameter fender washer painted black under the spike on top of white lid. Should be able to see that.
Another associate told me some are using cardboard cake beds. You can get them up to 16″ dia, cheap, tack them to a hub stake and forget picking them up.
Those Sky High Bull’s Eye look pretty good. Might go for that.
Good to get all this experience on here. No need to reinvent the wheel!
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I’ll check into the cost of adding the module into TBC. I don’t think it is free!
Looks like the photogrammetry module added to my existing TBC would be about $5-6000. Not happening at this time!
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Lee is correct. There is a high risk that the glare from the white lid will blot out any sign of the washer in the centre, or worse, you’ll end up with the light offsetting the apparent washer position so you only see part of it on some images – resulting in your control accuracy being lower and inconsistent.
Cost of the job is far higher than the cost of ensuring you have good control points. I suggest you set up a selection of different types in a local field and then fly them under different lighting conditions. You can then select the best type for your set-up and software.
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It used to be a free add-on. If you have photo processing covered, I suggest virtual surveyor for data extraction. Powerful stuff for a reasonable price. Demo mode works well and they have great tutorials. Blue Marble also has software to convert and reproject ortho photos. Probaly not something you need for a one off..
Good luck
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Interesting projects… I’m curious when all is said and done if using the drone actually saves any time/money/effort as opposed to just surveying the mile long gravel road.
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Me too…
But, I’m sure there’s a learning curve. Once you’ve done a couple of dozen projects like this; things should be flowing smoothly and a better comparison to how long it would take; compared to how it would take TDD.
I hope everyone has a great day; I know I will! -
Maybe I could paint them with some paint that reduces the glare, put a butterfly in another color on there. What colors are best to see in the pictures?
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If it doesn’t make you money, you’re doing it wrong. Of that may mean you’re using the wrong tool. In my experience corridor surveys are perfect for SUAS mapping.
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A 1 mile long drone project is actually quite sizeable when flying at the low heights and way more then i would recommend for a first project. You will have a significant amount of data to process. You haven’t mentioned how you plan to tie the ground control points. The 13mp camera may not produce the required project accuracies. We use the 20 and are always cross checking our data with on-the-ground checks, some good….some bad.
What platform is the end product going to reside in? You will need to work out the kinks in the workflow as well. I would recommend a smaller open square site or two first before you jump into a 1 mile roadway topo.
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What platform is the end product going to reside in?
I do everything as far as design and drafting within TBC. The road is very near to the house. GCP’s will be done with RTK GPS. Once the surface is developed I could load it into the TSC3 and check any point. Any elevation within a couple tenths +- is probably good enough at this point.
Maybe Trimble will let me demo the photogrammetry module for a while.
I’ll probably fly it all, then work on the smallest project first and go from there. No one is going to be damaged here until I get it right. Only loss will be my time. I can walk to this projects from my house.
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