I flew a flight yesterday over a 20 acre area. Everything went fine until I saw the processed map. A large portion is missing from the centre of the map. I can see the images that were uploaded did cover the whole area, but nothing appears on that part of the map. Any ideas why a chunk is missing?
Thanks!
Julian
Without looking at it, my first guess would be not enough overlap and/or flying too low. What altitude were you flying and what % overlap?
Flying at 200’. 60% sidelap, 70% frontlap.
That should be fine for bare earth. Were you flying over woods or structures or something? If you are in a situation that you can go back and fly it again, you could try 75% sidelap (or higher) just to see if that makes a difference.
I was flying over forest mostly. I thought I would get more detail if I flew lower. Will fly it again and change the sidelap. What about frontlap?
Thanks for the help.
Yeah, flying over forest can be a bit tricky. If you want to stay at 200ft elevation, then you’ll need to increase that sidelap. It still may not work, depending on the height of your trees…you may still need to increase elevation. You can leave your frontlap the same just for sake of the test. Also, I would go up to maybe 80% sidelap. It will increase flight time substantially though…so keep an eye on that.
Another factor in trees is wind. I’ve noticed if it’s a windy day, then the canopy shifts around constantly, so trees can look slightly different from photo to photo, making it hard for the software to stitch together. It will lead to blurring and swirling…which you may or may not mind. That said, making the above adjustments to sidelap etc. should get rid of the empty holes.
@JulianL
I have had that happen once and I just re-uploaded the image set and re-processed. That worked fine for my situation. I personally always have front lap at 80% because it does not increase flight time, just increases data set.
I flew the same property again, this time doing the whole 40 acres and again the map is missing all the wooded area (half the area). I bumped up the sidelap and frontlap to 75% but didn’t want to go higher to fly it on one battery. I was flying at 250’.
If I fly higher will it handle the trees better? The trees are pushing 100’ so the drone is really only 150’ above the tops.
Thanks for the help.
Hi Julian, I would definitely recommend flying higher for better quality, overall. Not sure if you’ve seen this yet but it should help if you haven’t. http://support.dronedeploy.com/docs/making-successful-maps