Hi - anyone experience in large scale mapping of forestry ?
Client in Ireland looking to survey 5000 acres of forestry, interested in boundary and encroachment in particular. I fly inspire 1 with x3 camera, currently on pro rate with DroneDeploy, but will have to move to business rate to cover the volume of photos. I’m estimating 15hrs flight time for this job.
Is it best to break the area down to sizable chunks? Is 70% side lap and 60% front lap sufficient for detail? Height of flight is at 70metres approx. Also what is average rate per acre where you are from?
Any help on this much appreciated,
Br
Declan
Hi Declan
Mapping forests can actually be quite difficult given that dense trees can look similar across images and have a complex structure (you can partially see through them) because of this I would recommend you fly at the maximum allowed altitude (probably around 100m in Ireland
On price per acre - our blog has a piece on pricing of services that might give you some ideas.
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5000 acres? I sub jobs like that out to an airplane survey crew who can shoot it with a 9 in camera or digital equiv in maybe an hour or less. They send me the digital files all orthorectifed and ready for delivery. I mark it up and make plenty for just making a couple phone calls and emails.
Love my drone, but sometimes its not the ‘best’ tool in the box. 
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That sounds expensive!
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5000 Acres will take a very very long time to do in a quad! I flew 750 acres with my matrice 100 with 4 sets of batteries and it took me approximately 10 hours over a 3 day period because of winter hours I could only fly between 1130 and 1300 otherwise the shadows grew too long. That time includes setup and travel to and from (30 minutes one way). I flew at 350ft through DD which put my speed around the 20mph. I did 75% and 75% on overlap.
For future jobs if I am going over 500 acres on one map I will look into a fixed wing asset as they cover much more area and can stay up longer. Granted they are very expensive, but with 5,000 acres you could probably use some of that income as a down payment.
Another issue you will run into is line of sight for that large of an area. I broke mine down in to 200-300 acre missions and I found it very difficult to see where my quad was, especially any time it was beyond 3/4 of a mile from my location.
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Declan,
I’ve found that the Mavic can do about 300 acres of forest in about 30 minutes at a mission height of 120m at sidelap 70%, frontlap 60% (default settings). This setting yields just under 1000 photos per 300 acre mission. Resolution at that height is excellent for forestry purposes. I haven’t run into stitching problems because at that height there’s enough variation in vegetation and terrain features. You might want to experiment with decreasing sidelap so missions fly faster with fewer photos to upload.
So doing the math, 5000ac / 300ac/mission = 17 missions x 30 min ea = 8.5 hrs of flight time. Add time for battery changes, sun angle, wind, LZ changes, weather, etc. and I’d guess it would take you between 3 and 5 days. Ireland should have some pretty long days in the summer, so if you have multiple batteries and a way to charge them as you go, it sounds doable.
As others have mentioned here, it may or may not be the most cost effective way of going though.
Caveot: your mileage may vary. I would definitely experiment with 300-acre tracts of forest before committing.
-Dan
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Hi Declan, large scale mapping is not for quadcopters. You should consider a Sensefly ebee and I happen to have a used one for sale. I map large areas for a living out here in UAE. Largest area I have mapped with ebee is 42 Sq KM. 20,000 images, 2 TB of deliverables. DroneDeploy is fine for small handy maps, but not large scale serious projects. The eBee is yours for USD 6500 including shipping and all accessories, 3 cameras, 4 batteries and 3 chargers. Once you use it, you won’t go back to quads.
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Thanks for the replies all. I’ve managed to grid out the area.into smaller manageable tracts, will try a small area first at 100m height and review,
Br
Declan
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@decmurray2010 there is also an app on our app market that you can install into your dashboard for pre- planning:
Click on App Market here-
Then scroll down until you see this one:
Then, when you plan a flight, it will tell you an estimate of photos and time to process.
We also covered large scale mapping in one of our webinars a few weeks back-
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Great thread and most informative. Also, I may have someone interested in your ebee. If still available, you can contact me on my personal email, vladimirlozinski@gmail.com
Map scale refers to the relationship (or ratio) between distance on a map and the corresponding distance on the ground. For example, on a 1:100000 scale map, 1cm on the map equals 1km on the ground.
Map scale is often confused or interpreted incorrectly, perhaps because the smaller the map scale, the larger the reference number and vice versa. For example, a 1:100000 scale map is considered a larger scale than a 1:250000 scale map.
Geoscience Australia has complete ‘small scale’ reference map coverage of Australia at scales of 1:2.5, 5, 10 and 20 million. We maintain a complete national topographic map and data coverage at 1:1 million and 1:250000 scale. We have an incomplete map and data coverage at 1:100000 and 1:50000 scales. We also produce digital products for several of these categories as well as a number of themed maps.
@VPS_DXB Hey. I am also working in the drone mapping field. I am a beginner so I am facing a lot of difficulties while mapping large areas particularly working with DSMs. Can you tell me what is the best practise to make DSM of such large areas and how to decide GCPs in that area ?
Thanks
Manish Sahu