We need to survey about 23,000+ Hectares of agriculture land and wondering what drone options we got given
(a) We have to survey really large area and small amount of time.
(b) We need to scan whole area say 3-4 times in a 8 months, over the season of crop to record growth.
(c) RGB + NDVI camera is good enough for now.
(d) Drone which is easy to repair, as I am sure there will be many crashes during operations..
Would it make more sense for to assemble it our own given we would need bunch of them, and we would need quick turn around time in case of repair/crash...
I understand that 23.000has are in the hole year in different days, different fields, not an only giant 23.000 has ortophoto.
Sounds like you are exagerating to make your own service sound better. He already doubled up the time to account for downtime. And also you keep ignoring the fact that operators can fly multiple drones at the same time and swap batteries/sd cards staggered. So 100 hours of flight time could be actually 5 days with 5 hours per day, 2 guys four drones with 1 spare. No downtime for parts, etc. and way cheaper than hiring a fullsize plane.
@Ben, excuse me, but I don´t agree that Darius Jack is exaggerating. I am not in favour of manned vs. unmanned, but I think his estimation is pretty accurate given the little information we have about this project.
It surprises me reading everyone throw logistic options without knowing the details of the project: Which is the purpose of the mission? Is there a single set of images or a series needed? what exactly is that he/they want to see from the imagery?, and most important: which is the adequate resolution? This last factor makes a huge difference in terms of acquisition times, manpower and computer horsepower when processing.
Thanks Jose (and others) for raising very valuable questions, helping us fine tune our thinking for executing this very large project. At this stage we would like to showcase that we can handle/survey large areas and effectively categorize a single crop (likely wheat) into three categories good, sick/stressed and dead, geo-tagged so that we can pin-point farm location. Any other information gathered would be nice but not required at this point.
We plan to create time series over the season to show how things are progressing, say 3 full surveys over the season (~6 month for wheat).
Hope this helps. Would love further feedback/suggestions from community.
@Darius, I only have experience with AgiSoft PhotoScan, but regarding the 2d to 3d conversion, if your data set is missing the required overlap, you get get a hole in your output. There is no missing information report during the conversion, nor does it tell you which segments are needed to my knowledge. It is possible to convert large areas in 'Chunks' using PhotoScan, so if you end up with spots that are missing the required information, you can re-sample a smaller area and add the missing photos to your data set, and then reprocess that chunk. The final output is created by aligning the chunks. You can also speed up the process by chunking up the data, which is recommended by Agisoft.
@Darius, Your comment, "Large project like this, don't get awarded by gov agencies to hobby modellers
like @RC or us."
Very interesting observation, but so true. However the Easter Island survey would seem to refute the notion that 'hobby models' can't do such a project. It's on the scale of 20k ha and was performed in 1 week by two fixed-wing drones.
Maybe this is why governments around the world are bankrupt - they can't seem to overcome their own biases that lead them to spend money in such a wasteful way, they ignore capitalistic solutions in favor of bloated, corrupted institutions that they have always used in the past.
We are developing a mapping drone in Estonia and flying with it for mapping service.
1) gathering the information is only the first step. We have quite a lot of computing power available, and it still takes us 3 days to get 15 km2 orthomosaic produced.
2) the number of photos will grow very fast when you increase the resolution. So you should aim at the lowest resolution possible.
Some figures on the number of photos are here: http://www.fotoglider.ee/aerial-mapping-service/
We have made some surveys for Estonian Agricultural Registers and Information Board and they required 20 cm/px. We flew at ca 400 m and made 10 cm/px photos for that (to be sure we are at required resolution after image processing).
3) even if you use cloud computing, it not for free. I advise to test out what is the lowest resolution you will need, before you actually start the project - you can save a lot of money on computing on a project of this size.
4) A lot depends on the accuracy of the aerial map needed - to get is "straight" you will need camera with IMU or a lot reference points on the grounds. Most "self made" UAV-s don't carry IMU.
Here is also the main advantage of the manned aircraft - the camera they can carry will give accurate results with just a few reference points on the ground and you will need less computing time.
UAV-s have advantage if yo need to cover small areas. I would think that on this scale manned aircraft is cheaper because of significantly lower image computing cost and less (or non) reference points needed on the ground. As mentioned in this thread: they can cover the area in hours and perhaps you get more comparable results.
your images look fuzzy, unsharp irrespective of preset resolution and altitude in your survey.
Have you tried to replace lens ?
Google Maps' sat imaginery sometimes feature lower resolution but still sharp imaginery.
Survey "23 Km2 3-4 times in a 8 months" with UAV it's possible but the cost/benefit is huge, because the post-processing data of 23 km2 is not easy. Also you need take in account flight time, weather conditions, cpu time consumption, fails, etc.
In my opinion the best solution to save time and money is a combination: Satellite-UAV a)To survey 23km2 --> Satellite images (e.g. Quick Bird resolution 0.65m, 5 bands Pan, B,G,R, NIR). After post-processing --> 2) UAV only if you need survey small critical area.
Yes, they are. These are made with two Canon S100. One modified to NIR and one RGB. I should probably add better quality photos from low altitude flight.