Hi. To the guys who are doing aerial surveys & mapping, and providing measurement data such as areas and volumes; When you provide data to clients do you qualify the accuracy, or make disclaimers about the information being provided? Without the use of ground control points the photogrammetry drone survey is a close approximation, so I am wondering what's the best way to cover this with a client. If I tell them that a muck-heap is 5,000m3, and it turns out to be 5,500m3 when they come to shift it, they may claim against me for the excess. Or is everybody doing GCPs for precise accuracy? (I'm using a H520)
Accuracy of survey data
- Thread starter Tone-Drone
- Start date
I think you'd work with a surveyor who can put their seal on the map if you want to claim accuracy, otherwise it's just a big picture.
It's not just ground control points, it's RTK-Real Time Kinetic update and a GPS ground station that gets down to centimeter accuracy. A Phantom 4 RTK with a cheap GPS ground station is lotsa thousand $, and the rigs surveyors use by Leica and their competition cost lots more. Intelligent ground control points are not cheap either.
Unless somebody's paying for a real surveyor who can prove the map's dead accurate and sign off on it, it's only an approximation. Go map a parking lot and see how many of the lines line up with the google map the mission was planned on, then try to figure who got it the most accurate, your drone or the satellite?
You might want to find a way to politely state you're not a certified surveyor, you've provided the best maps and estimates you can for cheap? My nephew-in-law and a surveyor sport about the country with RTK GPS rigs for their employer, and they're not cheap, neither is their kit...
It's not just ground control points, it's RTK-Real Time Kinetic update and a GPS ground station that gets down to centimeter accuracy. A Phantom 4 RTK with a cheap GPS ground station is lotsa thousand $, and the rigs surveyors use by Leica and their competition cost lots more. Intelligent ground control points are not cheap either.
Unless somebody's paying for a real surveyor who can prove the map's dead accurate and sign off on it, it's only an approximation. Go map a parking lot and see how many of the lines line up with the google map the mission was planned on, then try to figure who got it the most accurate, your drone or the satellite?
You might want to find a way to politely state you're not a certified surveyor, you've provided the best maps and estimates you can for cheap? My nephew-in-law and a surveyor sport about the country with RTK GPS rigs for their employer, and they're not cheap, neither is their kit...
PatR
Premium Pilot
Might be a good idea to use descriptive approximations. If we can’t assure the accuracy we should not mislead those receiving the data by assuring accuracy.
Thanks Guys. I appreciate and agree with your comments. I have started to offer a two tier service. A 'Premium' service, whereby I will provide an accurate survey by working with a land surveyor who will set out and measure ground control points and provide CAD drawings (and at a greater cost), and an 'Economy' service which will provide drone photogrammetry data only giving a 'good approximation' of the site. I just need to get the wording of 'good approximation' right! Anyone see any issues with this?
PatR
Premium Pilot
No issues, but as you already recognize, your wording will matter. I think you’ll find most that are interested in your service will only need the close approximation/position relative version.
