Hello fellow land surveyors!
I am currently looking for ways to improve my operations for producing topographic surveys as a one-man outfit by potentially changing methodology between office and field practices, including potentially changing equipment. My current equipment setup is a Trimble 2" S5 total station with a TSC7 for the field side of things and using AutoCAD Civil 3D as the office processing means. My current practices include using the total station to collect the proper amount of points to produce a topo and using Civil 3D's auto linework generator to speed up linework drafting and surface creation. I find this is very efficient compared to my competition and prior mentor-ship, but I really would like to try to reduce the manhour factor in both field and office practices to some extent. My particular interest is the Trimble SX12 simply for the fact I still need a total station for construction staking activities and general layout, but I can also harness the power of the laser scan to reduce running around with the prism pole to key in points and shoot curb lines, traffic stripes, concrete pads etc. I also realize that a laser scanner can't shoot manhole rims or property corners, but that's where the SX12 is so handy because I can get those standard survey pole shots for the topo.
Now that I've explained my end objective, I am curious if people have any experience with using a laser scanner to survey say a school property or even a single family residence to generate topos in particular with something like the Trimble SX12. Based on my research, I feel this would substantially reduce field hours because of the speed of the laser scan compared to a rod and prism for data collection, not to mention the more accurate terrain detail you would get from a scanner compared to 25' cross sections with a total station. In theory, this would substantially decrease field time, but I understand that you are trading that time for more office time to sort the collected data out. I also know you lose the functionality of Civil 3D's auto linework generator since you aren't creating cogo points with descriptors to execute the program, but I believe using the point cloud you quickly make up for that lost time drawing the lines at the drafters discretion plus you wouldn't need to clean up errors from coding to draw the linework for said topo. In addition to this I feel surface creation would go faster and be far more accurate because of the built in point cloud surface creation feature in Civil 3D. Regardless of my thoughts, I'd love to hear feedback on the community on my proposed workflow and the pros/cons of using laser scanning for topo creation compared to the conventional total station point collection and drafting.
Another question I have is how people feel about sighting targets moving from a standard Trimble Total Station to an SX12. Relying on cameras and a data collector to site a target is hard for me to get my head wrapped around when I've been using optics for years. I've heard some people say there is no difference between both methods, but I'd like to hear real world feedback from surveyor's that have actually made the switch.
Thank you all for your interest in this topic and I look forward to your feedback!
I could write a paper on the benefits of using a scanning total station, but suffice it to say that I highly recommend it. If you are tech-savvy, have a solid grasp of the pros & cons of laser scanning, and don't mind putting some time and effort into optimizing your workflow, you will run circles around other solo operators.
You didn't mention whether you had Trimble Business Center - I would assume so since you are already using Trimble. You're going to need it to really maximize your workflow - specifically, you're going to need the scanning module. That is what will really make your gear sing.
Classification and feature extraction is very intuitive, and you can literally "survey virtually" once you have gotten a handle on the workflow. You don't have to run cloud to cloud registration, but it's there if you need it.
The folks who complain about using a camera for sighting are inevitably those who have minimal time spent getting acclimated to it. Especially on an SX10/12 with the incredible optics. It's a learning curve like everything else.
I am a one man crew myself and I've gotta tell you, the best way to go about a TOPO without a Drone is with a Base and Rover GPS unit on a 15FT prism pole, the prism pole allows you to achieve a good fix, otherwise unless it's wide open it's gonna be slow going.
@rover83?ÿ
Do it.
I'll read it.?ÿ I'm still building my skills in that arena. I love the environment.
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I was slightly suspicious of the whole camera and no sight, but after closing traverses at near performance max specs several times, I'm sold. Of course there is more that can go wrong, so paying attention to standard routines like columation and calibration keeps the equipment honest and you too.
Nothing is infallible, and knowing when and where things " don't look right" is part of the long haul of this job based on the experience gained by all the time on station we spend.
That said the SX10 and 12 are a great addition to the tool box.
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This is actually something I'm doing currently - full site surveys with laser scanner, with the exception of some features to be surveyed conventionally. However, the deliverable is not a traditional survey topo/detail plan, which is why I can do that.
If the deliverable is a standard detail CAD plan, then for most scenarios conventional surveying with a total station will be faster than a laser scanner. The laser scanner gets better as the complexity increases, and you start running into things that aren't easily described or drawn with standard survey coding and points and lines. The laser scanner gets really, really better when the deliverable is something point cloud based, or the complexity of the scene is very high.
Main reason why is that virtual surveying is rarely as quick as picking things up in the field for basic surface features.?ÿ
The typical product I prepare is a standard detail CAD plan. That's one thing I was curious of if the standard product is a dwg file and cogo points are usually shared, is it still faster to do a hybrid of scan and conventional shots or just go standard conventional all the way through.
What about this workflow? Say you do a hybrid approach, but then you take the field data and then calc cogo points in Civil 3D for the feature collected from the laser scan, rather than walk up to the points and take a shot? So calc curb points coded as TBC, TBC PC, etc. This would still significantly decrease the manhours for fieldwork, while allowing you to essentially "virtually survey" the project from the comfort of your office where you're not subject to the elements. I also see this as a great way to significantly reduce coding errors, plus you can use the Civil 3D auto linework generator as well from the created cogo points. Plus you have an even more detailed data set, should a client be able to understand those file types. What are you thoughts on going this route?
I've done quite a few topos from scandata and the problem is without a software like topodot it is extremely difficult to digitize stuff that's curved.?ÿ
When you're in the field you can easily identify the start of curve of a line, with scandata that is more difficult.
I tend to scan everything and get everything that is above ground like trees, light poles, traffic signs,... from scandata but gutter and curb i tend to measure conventionally again. To much time wasted pc in laserscandata.
Contour of buildings etc are all from scandata. It's just monuments and roadlines conventionally. Only if the conditions are dangerous like on a intersection i tend to digitize from scandata for my own safety.
I must say i'm also quite interested in a robot like the sx12 to perform floor analysis and other high precision stuff, not because the scanner isn't good (A Riegl VZ400i is top notch) but you could stakeout problem areas from scandata with the same instrument.
scanning can be good with a SX10/12 for safety and places you can??t access, bridges. It depends what you need in the end. That is do you need to place a cogo ?ÿpoint on the scan for use in autocad or microstation? If so you??ll be spending more office time placing points that could have been collected possibly in less time in the field.
You will also pay about $8000 for TBC and scanning module if you don??t have TBC already. You could consider the X7 that??s a much faster scanner with 80m range.?ÿ
also consider GNSS receivers that receive all 4 constellations with a rover being R12i. In open areas I??ve found RTK with 4 constellations being most times as accurate as robotic for elevation.
as one person replied using a 15 foot rod, that isn??t needed with R12 and 4 constellations, just 2m rod. GNSS might be more productive for you since you eliminate line of sight requirement.
@ktmranger1 I would be 99% confident that for typical detail surveys with a road x-section every 10m or so, I'd be faster running purely conventional, especially as the working distance from the instrument with conventional is ~100m or so, whereas with a scanner, you are down to around 25m or so for shallow angle points like gutters.
@ktmranger1 I would be 99% confident that for typical detail surveys with a road x-section every 10m or so, I'd be faster running purely conventional, especially as the working distance from the instrument with conventional is ~100m or so, whereas with a scanner, you are down to around 25m or so for shallow angle points like gutters.
That's when you break out the mobile scanner and just drive the corridor. ?????ÿ
I do agree - for very basic topos a scanning TS isn't often going to increase productivity. As @beuckie mentioned, it's all about knowing what is faster to scan and what is faster to observe conventionally.
But as soon as my field environment moves into "urban" territory and/or I have a lot of hard surfaces and complex objects in my project area, I'm going to start scanning.
If nothing else, I am going to avoid two hours having to walk that whole parking lot, when I can just grab a scan or two, classify ground and extract points at 10 ft intervals. (I will also use the cloud to tag parking stripes, which are tedious and time consuming to shoot conventionally.) I'll grab whatever curb & gutter I can from the scan, but conventionally shoot breaklines that the scanner can't see well.
It's as much about proper planning of station setups as anything else, as well as a very good understanding of what is faster to shoot in the field vs scan and survey in the office.
For an typical topo in a complex urban environment, a scanning total station with an experienced field AND office operator (who is both scanning and taking conventional measurements) is going to outperform a conventional topo. The problem is that most folks are missing that experience and are unable to think critically about when to scan and when not, and end up wasting time.