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kind of funny but interesting article on UAV mapping accuracy

R.Perry

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Sounds like surveyors protecting their jobs, can't blame them. First of all, I have done many mappings for various companies. Used their GCPs to get as close as possible on some of them.
Reality is, the mapping isn't used for surveying, but viewing jobs site, volume and pile reports, downloading to Auto Cad, and inspections. I have had building department folks use my mappings for their inspections where applicable. Bottom line is drone mapping as we call it is used for many purposes, and surveying isn't one of them. However, as technology goes, it won't be long and drones will be replacing some surveyors, or become a tool used by survey contractors.
 
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durapitch

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Sounds like surveyors protecting their jobs, can't blame them. First of all, I have done many mappings for various companies. Used their GCPs to get as close as possible on some of them.
Reality is, the mapping isn't used for surveying, but viewing jobs site, volume and pile reports, downloading to Auto Cad, and inspections. I have had building department folks use my mappings for their inspections where applicable. Bottom line is drone mapping as we call it is used for many purposes, and surveying isn't one of them. However, as technology goes, it won't be long and drones will be replacing some surveyors, or become a tool used by survey contractors.
Looks like you need to review what surveying is, it certainly is not just boundary. If engineering calcs are being done using your maps, and your not entirely sure what your doing, you could open yourself up to significant civil liability. But you'll probably be fine and confirmation bias will rule. GL
This is a truly hilarious statement "Bottom line is drone mapping as we call it is used for many purposes, and surveying isn't one of them". Just to refresh your memory of 'surveying defined'in California state law:
(a) Locates, relocates, establishes, reestablishes, or retraces the alignment or elevation
for any of the fixed works embraced within the practice of civil engineering, as described in
Section 6731.
(b) Determines the configuration or contour of the earth’s surface, or the position of
fixed objects above, on, or below the surface of the earth by applying the principles of
mathematics or photogrammetry.
 
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Dave Pitman

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The blog writer promotes using check shots (he doesn't call them that) to determine general overall accuracy of the processed surface. What a novel idea......wait...what?.
Not novel at all acutally as that is the method recommended everywhere I have ever seen. Mayve he should have read a few more mapping forums...or the correct ones!
 
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durapitch

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The blog writer promotes using check shots (he doesn't call them that) to determine general overall accuracy of the processed surface. What a novel idea......wait...what?.
Not novel at all acutally as that is the method recommended everywhere I have ever seen. Mayve he should have read a few more mapping forums...or the correct ones!
please show me where FGDC standards and 95% confidence levels are discussed... I dare you. RMS error is not legally biding (the only approach I've seen pushed) and will give you overly-optimistic error estimates by a factor of 2. Nobody want's excess legal liability, and following FGDC 95% confidence level recommendations can go a long way towards fixing that.

I won't even get into putting proper control constraints on your GCP to get true 'network accuracy'. And I certainly won't get into the necessity to include inherent error in your geoid realization in your final error number. But go ahead and read these forums, I'm sure someone has those answers for you. LOL
 

Dave Pitman

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I take it you are the blog author? I'm sorry you are offended. Do you understand how to use check shots in your workflow? They are completely independent of the software's processing and will demonstrate the real error between the derived surface and independent survey. Which is the point you are trying to make, right?
 
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durapitch

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I take it you are the blog author? I'm sorry you are offended. Do you understand how to use check shots in your workflow? They are completely independent of the software's processing and will demonstrate the real error between the derived surface and independent survey. Which is the point you are trying to make, right?
Not the author, but I've seen him speak at conferences a few times. The dude knows what he is talking about, I'm sure you both could have good conversations... or not.
Obviously I use independent checks as you may be able to infer from my previous posts. I have 20 years experience doing 'big plane' LiDAR and photogrammetric reduction. I'm also not a surveyor, but I've worked alongside them for years and am full aware of the legal consequences of not properly checking and reporting accuracy.
 

R.Perry

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Looks like you need to review what surveying is, it certainly is not just boundary. If engineering calcs are being done using your maps, and your not entirely sure what your doing, you could open yourself up to significant civil liability. But you'll probably be fine and confirmation bias will rule. GL
This is a truly hilarious statement "Bottom line is drone mapping as we call it is used for many purposes, and surveying isn't one of them". Just to refresh your memory of 'surveying defined'in California state law:
(a) Locates, relocates, establishes, reestablishes, or retraces the alignment or elevation
for any of the fixed works embraced within the practice of civil engineering, as described in
Section 6731.
(b) Determines the configuration or contour of the earth’s surface, or the position of
fixed objects above, on, or below the surface of the earth by applying the principles of
mathematics or photogrammetry.

What we do is supply information to the client, and they use it as they see fit. Example Drone Deploy has proven to be very accurate on with their volume and pile reports, at least accurate enough for the clients needs. Building inspectors don't need survey grade accuracy to view a project development and they understand that the reports we give them will not meet survey grade standards.
I have had many conversations with surveyors and many of them see drones as a future threat to their jobs, and I can fully understand their concerns.
When I was working the UC Merced job they were using my mappings for volume reports on the excavation for building footings. The engineers compared my mappings with surveyors, I was told, quote "close enough". No it wasn't dead accurate, but accurate enough for their purposes. Also I wasn't using a RTK drone.
When processing a Drone Deploy mapping if we have the GCPs from the surveyors our mappings come out very accurate.
From the tone of your post it seems obvious you have issues with drone mappings, that my friend is your problem, not ours.
 
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R.Perry

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In regards to the future of drone mapping accuracy I believe with the use of RTK drones and future technology we will see drones capable surveying, and doing it much faster than manual surveys. All one needs to do is look around and see how fast various technologies advance and the hand writing is on the wall.
 

durapitch

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What we do is supply information to the client, and they use it as they see fit. Example Drone Deploy has proven to be very accurate on with their volume and pile reports, at least accurate enough for the clients needs. Building inspectors don't need survey grade accuracy to view a project development and they understand that the reports we give them will not meet survey grade standards.
I have had many conversations with surveyors and many of them see drones as a future threat to their jobs, and I can fully understand their concerns.
When I was working the UC Merced job they were using my mappings for volume reports on the excavation for building footings. The engineers compared my mappings with surveyors, I was told, quote "close enough". No it wasn't dead accurate, but accurate enough for their purposes. Also I wasn't using a RTK drone.
When processing a Drone Deploy mapping if we have the GCPs from the surveyors our mappings come out very accurate.
From the tone of your post it seems obvious you have issues with drone mappings, that my friend is your problem, not ours.
I completely understand, and I have zero issue with "close enough" drone mapping. More power to you. Just be aware, even though your client says "good enough", I would want that in writing and signed by the client. I have seen multiple civil suits from the result of sub-par practices, and even though your client is good with the map, it will most likely be shared with others who are not aware of your verbal agreement. One such lawsuit was a 'drone mapper' who was contracted by a waste managment company (not to be named...burrtec) in california. He supplied mapping in waste's coordinate system. The GCPs that waste provided had 3'-4' in vertical plane tilt and 5' in relative error on some points. The 'mapper' threw out a few GCPs until he matched that skewed vertical plane and supplied a map. They then spent $200k using that mappping on SWPP design, then contracted a surveyor to lay it out. Long story short... the design was worthless and Burrtec went after drone guy with a massive lawsuit. Burrtec won, and he is now in a bad place. The bad GCPs were no excuse as proven by Burrtec's lawyers.
Once again... I have no issues, it is your risk to take, but lawyers don't care about your past jobs or verbal agreements or 'good enough'. I have seen it and I just want to warn you. A signed document between you and the client stating that the mapping has no claim to accuracy could save you big time.
I don't know many surveyors anymore who see drone mapping as a threat. Most crews around here all have one on the survey rig, and unions are requiring FAA 107. There is a niche for non survey grade and one for engineering grade (with boundaries). No reason why everyone can't be happy.
 
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R.Perry

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In our contracts we make if very clear that our mappings do not meet survey standards and if they need that accuracy they need have a licensed surveyor produce it. That is just good old common sense.
You are correct that one must always CYA, how do I know. Wife was a lawyer.
 

durapitch

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In our contracts we make if very clear that our mappings do not meet survey standards and if they need that accuracy they need have a licensed surveyor produce it. That is just good old common sense.
You are correct that one must always CYA, how do I know. Wife was a lawyer.
LOL!!! I'm preaching to the choir. And you are saint in my book, marrying a lawyer. Have a good one.
 
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