Contracting Lidar Jobs

Hey folks. I wanted to share an experience with my fellow Lidar users, and see if anyone here has dealt with anything similar, and possibly has some feedback. We are a land survey company of 40 years, and have a long time engineering client that is a very good client of ours. We recently proposed a job for them that included using our Rock LiDAR system to supplement our survey. However, our local county (the end user of our survey) has an office of county surveyor, that is suggesting in a condescending way to our client that “we surveyors don’t know how to use LiDAR” Are there any surveyors here that could tell me how they might respond to something like this?

Odd, the county surveyor says he understands the technology but is does not appear to be the case.
We are a survey company in California, and with all new technology there are checks and balances.
With every Lidar project, we confirm and check the data. I assume you are doing the same.
Lidar is a very good tool for surveying. The county surveyor really should not be dictating which method you are using. You are stamping and signing the survey.

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Lidar Lidar Lidar… I can understand their reticence to acceptance if the only lidar data they have ever used came from a “commercial” supplier. I’ve come across this problem a few times, the “commercial” lidar data is typically 0.30-0.50m resolution. The engineering company where I came from LOVED this stuff… it was comically cheap and slightly better than google earth…

Until you see what ROCK can do!
Perhaps this individual would like to sit down with someone from here to witness the truly awesome data feed that is ROCK Lidar?
I’ve worked hard on a client that could not see the forest because there are too many trees in the way. It was a journey to quell their anxiety (they’re scared of everything), from proving the control shots to understanding how the data is collected, calibrated and can be shifted (they’ve used fictitious control points, but we caught onto it and moved the data). We compared our lidar to the ground shots and discovered that the traditional survey miscalculated by 20,000m3!! Why? Taking shots every 10m or more versus every 10mm… they literally missed thousands of cubes of material. Oh, and they took two weeks to do this. AND they still had issues (staffing, changing site and too much detail to capture by hand).

I would ask the County for 30 minutes of time and show case how this truly works… I am betting they’ve been burned in the past. IT would not be the first job that needs to be cleaned up from bad operators. Emphasis the use of ground control shots, checks and balances and don’t be afraid to show some failures.

Good luck!

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Absolutely. I’m actually pretty skeptical about his claim that “surveyors think its a magic box” We have been in business for 40 years, and have overseen the adoption of new technology the entire time. Our owner and senior surveyor recalls the time when he bought their first electronic disto-meter. That was the “magic black box” of the 1970’s. I highly doubt any licensed surveyor would just accept a lidar data set, and produce a survey without proper data checks.
One question I have for any surveyors here is: Are there any set of industry standards for proving your data? I have been checking against my GCP’s, having my crew grab some scattered ground shots around the site, and also on hard surfaces, I’ve been getting a survey grade cross section about every 500-800 feet to check my lidar. (We still are using conventional survey techniques for storm structures, pipe inverts, utilities, etc.) I don’t think anything we say will make this guy less arrogant, but I’d like to provide him with some type of industry standards for quality control that we can use on his project. Does anyone have any info on LiDAR industry standards?

Are there industry standards for Lidar data? Should we just make some?
As a professional survey company, we check and check and check our data against known benchmarks.
We never take Lidar as “gospel” and we aim to provide survey that is “golf ball” accurate (+/-25mm). Our R2A can make this grade all day long.
I am curious as to what they deem “acceptable”… if they want it THAT accurate, what have they been using until now? By hand? LOL

This may not go over well but I agree with him. I have seen way to many cases where a surveyor provided an engineer with a “topo” generated from LiDAR. Engineer designs his project using said data. Project goes under construction, contractor ends up with a LOT of extra dirt or not enough dirt. We had a client tell us just the other day his engineer used LiDAR only to find out when under construction his site only has 0.70’ of fall. This one will go to litigation. We only use LiDAR data as a supplemental to our conventional data. The data we get compared to a conventional survey is usually good, most comparisons are plus or minus .5’, but we have run across areas where it is 3-5’ out. When designing in flat environments like we work in, LiDAR alone is just not accurate enough to use for design, unless you are willing to take a big risk. Just like with any of our other data acquisition methods, they all have there applications and use, its up to the Surveyor to use them to provide the client with the best data they can, unless they specify contractually otherwise. As for “standards” most states refer to the National Map Accuracy standards or to FGDC standards.

We have yet (after many flights) achieved that kind of overall accuracy in the woods, what’s your secret? We will have some random checks dead on, but we will have others out a foot or more.

Mike, initially, I was having some issues like that, but I realized that I wasn’t using the correct workflow to generate my TIN and check against the Lidar data. Once I figured that out, I don’t recall seeing any shots out more than 0.25’. It wasn’t the Lidar data that was off, it was my method of applying check shots.

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I’ve only worked in Urban forests…
Fly slow, fly low. We fly by hand (up to +/-100ac), and our overlap is substantial in this type of environment, almost 80%.
Our check points/targets are high visibility and we create many check shots/points.

In my past life, as a consulting civil engineer, dirt balance, fluff and shrinkage are always “issues” and more than once I’ve had discussions with the dirt contractor, who is claiming their rock trucks haul 30% more capacity than physically possible, dispute numbers. Its a shitty world that way.

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in Georgia, the state surveyors board has adopted new standards for aerial LiDAR, but the Gov has not signed into law yet. We adopted those proposals Aug 2021 even though it’s not legally required. It helps to substantiate the data accuracy. We took an additional step by developing our own Accuracy Report, to further support the LiDAR results. ALL our licensed surveyors have ZERO hesitation of signing off on any LiDAR project we fly.
Minimum survey grade standard acceptance allows for so much variance, based on acreage size. Our R2A easily exceeds that every single flight.

If you’re doing 1-ft contours, then the acceptable “survey grade” is less than 1/2 foot variance. The R2A blows right by this every single flight. You just have to determine how you are packaging all the data, so the viewer can easily see the end deliverable is WELL w/in that.

HOORAH to the Rock Team for making this a non-issue!!!

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Mike

Do you have some examples of this type of data that we could have a look at? I think if we can have a look at it in more detail (perhaps with a trajectory and ppk_report) then we can assess your capture techniques and determine where/why you are seeing a loss in accuracy.

I think I’d just point out that they don’t need to know how to use it (assuming it’s not part of the deliverable). It’s just one data collection method used to create the deliverable that, as surveyors, you are using like every other tool in your arsenal…

True. As it turns out, we know some other people at their office. We were told that they spent a ton of money a few years ago on a system that is difficult to use. I’m pretty sure he just has LiDAR envy.

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We can send him a quote :slight_smile: