Ep7: GCPs vs RTK vs PPK | Accuracy in Drone Mapping | Hammer Missions

[@robbradshaw5534]

Well done guys! I'd just like to add, whether on purpose or a happy accident the list of topics you cover on the right side of the screen is BRILLIANT! After watching fully through the first time my subsequent visits it allows me to quickly jump directly to the part I want to hear again. This should be your hallmark, actually this should be the hallmark of every educational KZbin video!

[@HammerMissions]

Great to hear you enjoyed the video and thank you for your kind words!

[@bryanspelhaug2135]

We always have a need on our jobsite to check elevation for say spoils haul off. We are currently using Drone Deploy with Emlid survey software to collect data for GCPs. It works well but it is time consuming for setup sometimes. You mentioned smart GCP's, I'm interested in looking into that workflow. Might save time and money! Has anyone on your team used the smart GCP method?

[@sebastiandemuria4317]

(Message 1/2) Hello team, I liked your video, it accommodated my lack of understanding of some things regarding the three processing methods for geolocation of image sampling. I would like to ask you just 2 questions: 1.- IF you had to acquire equipment to make 2D/3D, orthomosaic/lever curves, points cloud, DEM models in mountains with forests, and smooth areas such as roads or old bridges to remodel ===> What equipment would you use? Was this team good? ==> M350 RTK, Zenmuse P1, Zenmuse L2 or PhaseOne IXM-100. 2.- Today the market is already equipped with many of these Mapping activities. With the equipment mentioned in point 1, it could make a difference in providing a higher quality service or it is not worth the effort to acquire this equipment because there are other processes. PPT that improves the quality of deliverables to the client. 3.- How could I match or get closer to the precision and results of the millimetric measurements of the millimetric equipment of traditional conventional surveyors? Could this PhaseOne IXM-100 40 MG pixel camera help or not? 4.- If I implement RTK, 3/4 of the time of surveying 200 hectares, my RTK GCP loses connectivity, could I continue surveying the sampling and then process everything with the PPK method? @sebastiandemuria4317 🤔

[@HammerMissions]

1 - There isn't a single absolute best equipment! We suggest reading our guide on how to buy the right drone: www.hammermissions.com/post/how-to-buy-drones 2 - It all starts with identifying a niche (small segment of the market) and serving that niche better than anybody else using your competitive advantages! 3 - Accuracy of the dataset has less to do with the camera and more to do with whether GCP/RTK/PPK was used. kzbin.info/www/bejne/m3_ao4t4qrKkkMk 4 - Yes, one advantage of the PPK / GCP methods is that they are not real time method, so even if you lose connection, you can use to create higher accuracy outputs! Hope this helps!

[@sebastiandemuria4317]

@@HammerMissions Thanks for your prompt answers. 🙂

[@sebastiandemuria4317]

Message (2/2) 5.- Could you make a video with the differences between photometry and LiDAR? I understand the topic, but I would like to know more about where each one applies, I understand that LiDAR is better in forests, while photogrammetry is better on surfaces or to make orthomosaics It would be good to hear your experience on the subject. I am analyzing all this information to learn whether I could invest in a business that might offer a difference in the service outputs. Nowadays, many companies are providing this service, and I am wondering whether I can offer something better. Do you think this could be reached? Any comment would be awesome. Thanks for reading my comment. Kind regards. Sebastian

[@sid4276]

Nice explanation thanks.

[@brendanbrady3431]

Ok you mention using survey grade equipment for positioning GCPs, then say later that it's a low up-front cost method

[@HammerMissions]

It's lower upfront cost as RTK drones or PPK software are not strictly required. It's more expensive in time spent layout the GCPs! 🏁

[@JonWitsellPhotographicArts]

@@HammerMissions What's expensive is the GNSS receiver you need to accurately locate your GCPS-or the surveyor. Later you said you just put them down, but they are useless as ground control unless you have them accurately located. They are NOT low cost upfront. GCP targets: $100. GNSS receiver: $6K for our EOS Arrow. Emlid will get you cheaper.

[@HammerMissions]

@@JonWitsellPhotographicArts Our point was that all things being equal, they are lower cost than RTK or PPK methods as they do not require you to purchase an RTK drone, which at the time were typically higher priced than non-RTK drones. The cost for RTK drones has fallen sharply since and almost all new enterprise drones now have RTK enabled (yay!). And yes, we do recognise that the GNSS receiver can also be cost prohibitive! 👍

[@JCDiaz-Skytech]

Varun, Alex, is it true that RTK would help to minimize signal interference if flying near electrical or cell towers while inspecting them?

[@HammerMissions]

Hi Juan! Some sources claim that RTK helps combat magnetic interference but we haven't tested this internally and would recommend checking this with DJI themselves. As a rule of thumb, it's best to takeoff the drone manually first and check how it behaves on site before commencing an automated data capture. We are normally seeing RTK employed more in mapping applications than inspection applications, as RTK's primary purpose is to increase the accuracy of the data as opposed to combat signal interference. Hope this helps!

[@mricqball3986]

Hello sir, I still confuse about the diff between ppk and gcp. Is the ppk do not need to put the marking point on the ground? I heard about CP- checkpoint for ppk? Is it like same as gcp?

[@HammerMissions]

Hi there, thanks for the question! PPK traditionally does not require GCPs on the ground but useful to have them as backup case RTK signal fails. Generally speaking, PPK relies on having an RTK-enabled drone and post-processing the RTK readings. Here's on PPK: www.hammermissions.com/post/drone-ppk-workflow-with-hammer-missions

[@jerseyshoredroneservices225]

A checkpoint is the same thing as a ground control point but it's used differently. it's kind of like when you do a math problem. When you get the answer... then you do the problem backwards to see if your answer was correct. Ground control points are used to pin down the map in several locations. You normally put some around the perimeter , at least one in the middle and you try to position them so that some are on the highest and lowest elevations of the site. Checkpoints would be somewhere in between the ground control points. You don't pin the map down to them you check to see how far the map is off from them. So basically imagine that your checkpoint was surveyed at 1, 1.2, 2 but in the map, the checkpoint appears at .5, 1.6 and 4. Now you can calculate your accuracy and see if the map is good or not good enough.

[@inve]

Now we need a video on smart GCP and how it compares, especially on price vs RTK. Also, which is the most accurate method, one would assume RTK. Great video and very informative! Thanks.

[@HammerMissions]

Great suggestion! And thank you!

[@nafnist]

GCPs can be as accurate as you like, really.

[@inve]

@@nafnist Agreed but my reference was towards “Smart” gcp’es. Imagine setting out L2 gcp’es, no need for a rover.

[@vp62ift]

Gcp have to be survey grade gps location points ?

[@inve]

@@vp62ift there are new GCP that have GPS units integrated into them. Hence smart GCPs. I believe they’re L2 level.

[@ammadahmad3549]

Very effective and informative discussion please elobrate it practically if possible

[@PrasitSookrob]

Good job

[@Dangit-Dave]

This podcast just left me more confused.

[@HammerMissions]

Oh no! Can we clarify something?