How possible would it be for a municipality to capture it's own orthophotography of the approx 22 square miles city limits??ÿ My idea is to lay out the city and fly it in small sections or neighborhoods.?ÿ?ÿ
Basically, what we have is:
DJI inspire(2 or 3) and a Mavic Pro2
Trimble R8-2 GNSS running VRS for control points
High accuracy DEM created from Lidar
We would need to purchase imagery processing software that meets or exceeds our standards.
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I understand that our flight times and missions are limited to battery capacity.?ÿ ?ÿI also understand the issue with leaf off season, sun angle, and weather permitting.?ÿ ?ÿWhat I want to know is, how doable is it??ÿ And could we meet, or exceed the 3 inch GSD we purchase every 4 years?
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Don't crucify me, I'm just an old Marine thinking out loud here.?ÿ I'm trying to apply the improvise, adapt, and overcome mindset to our city's fledgling UAS program.
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Thanks in advance!
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Possible, but would take forever and cost more than manned aircraft. From experience with flying large areas over multiple days...targeting, lighting, site conditions, and changing weather conditions. We tried to fly about 1200 acres with a Matrice 210. It took over 30 flights and was a nightmare. We upgraded to a Wingtra One fixed wing and flew another site that was 1700 acres - still took 12 flights and multiple days. Save yourself the headache and have it flown by a manned aircraft. They will be done in one day.?ÿ
Another item to consider is the boatload of images you will have to deal with - 22 miles will be measured in ten of thousands of images and processing will take weeks for the machine to crunch it all.
Sounds a bit like cleaning the floor with a toothbrush. Possible yes. Practical no.?ÿ
Not to mention the FAA rules about flying over people and cars would certainly be in violation if an entire city is flown?
Come on, according to all of the Drone workshops and webinars, those FAA rules are really just a suggestion.
Cost for 24 miles of utility corridor, two small towns of 1600 people, $20,000 from one of the big Lidar companies. Plus 8 control panel points.?ÿ
Cost to do that with a drone, from what I've seen 10 times as much. At least.?ÿ
The work runs into an economy of scale, is it possible, I guess, but practically it's not possible, go with the big boy pros for that.
I doubt you will be within 10x the price.?ÿ
The cost of getting the plane in the air swamps the cost of doing a 20 acre topo with the drone, but when you have 22 sq miles, they will do it in one day, then they have the same data you have after weeks of picking at it.?ÿ
If it's T and M with a 4 or higher multiplier jump on it.?ÿ
I'm thinking a hybrid solution may be in order. The cost of the photos alone, via airplane, is often not that great.?ÿ Especially if it doesn't have to be done on a specific day or week. My understanding is that can be around a couple thousand dollars. So you get?ÿ an airplane to take the photos, then you do the data reduction. Perhaps you could then use your drone to do "infill" - add new developments, detail special areas, etc.?ÿ in between the quadrennial efforts.
Drones and photos are neat, but the network of control you will need to support it is going to be really valuable as well.?ÿ?ÿ
@norman-oklahoma Mark, you are on the right track (more phased than hybrid) and in case anyone is still interested in this old thread, our mapping firm has done a number of projects where we have done kind of a map maintenance program. Acquisition maybe one year and then deliver the data the next year and then rinse and repeat. It is economical to keep everything on a 2-3 year schedule, nothing gets too dated and the customer gets to spread costs over 2-3 years. Control isn't too out of date, maybe just needing new targets and maybe no new survey control. We have been mapping some cities/counties like this for 20+ years and is definitely worth considering vs doing it once and then 10 years later doing it again from scratch.
I suppose software could be purchased by the customer but you probably actually need a photogrammetrist who understands the process on staff and can head up the program plus the proper software and hardware in place, AFAIK, we have no customers that do this, at least with something like Pix4D, etc. We do sometimes do acquisition only for large agencies, BUT they have a mapping department inhouse, just don't have the acquisition capability.
SHG
What is the end product desired? Do you want contours to 1 foot, 2 foot, 5 foot? How accurate does the Cadastral end product have to be?
Another item to consider is the boatload of images you will have to deal with - 22 miles will be measured in ten of thousands of images and processing will take weeks for the machine to crunch it all.
It's not just the number of images and the time: it's having the hardware which can cope with them all and the software which can d the necessary. No good splitting it up into 44 smaller groups and hoping the edges will match - they won't! The software you need will probably cost more than putting up a manned aircraft - they will already have the software and hardware. The suggestion by others that you just use the drone for future fill-ins is possible but even then it might be cheaper for several local authorities to get together and fly a whole area for a day once every three years. The real cost on manned aerial survey is getting the aircraft airborne: once it is up the extra mileage is nearly "free". The drone problem even with fill-ins is that you might still have to fly the whole area if the development is scattered all over. You can guarantee it won't all be in one small district.
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Mark, you are on the right track .....
Since I wrote that entry I have taken a job with my local city. A city of about the same breadth as that of the OP. I am told that drone-ing up was once considered,?ÿ but nixed by the PW Manager because the spectacle of government owned drones hovering over the citizens was considered abhorrent.?ÿ ?ÿ
The city subscribes to a service called "Nearmap" which supplies georeferenced imaging. The images are updated twice per year in this area and have pixel sizes as little as 4cm. I have no idea what it costs.?ÿ No surfaces, etc. But good vertical images on demand that make great backgrounds for my topos.?ÿ
