Capturing underground utilities while the pit or trench is open has always been a best practice, but not practiced enough. This has now become so simple that reasons not to document are running out.
Underground utilities in NYC – Image source: Doug Blizzard
The golden opportunity to properly document assets before they a buried is all too frequently missed. The excuses to skip or skimp on this valuable step are not completely without merit: It can be a time consuming and costly proposition, and has best been performed by surveyors and inspectors with careful measurement, precision tech, and specific documentation steps. Certainly, 3D reality capture technologies have risen to the cause; providing photogrammetric and lidar-based solutions that speed up capture. But for many practitioners, barriers to broad adoption appear to still stand in the way. And in asset data management: how to connect, store and share. No longer.
Waving the Magic Wand
Has the process become as easy as waving your phone over the pit? In short, Yes. There are a range of options that can be deployed to just about anyone with low-cost equipment and minimal technical training. With all of the people that are working around the pit, there is almost no excuse for any of them not grabbing the data.
While there are more formally developed tools and technologies for such rapid capture, even a standard phone with a camera is up to the task. With the help of purpose designed apps, you can walk along a trench, capturing a series of images that can be processed in the cloud (or later in desktop applications) to yield a photogrammetric 3D point cloud. Upload it to a repository, or asset management portal, and in minutes you’ve provided valuable, somewhat precise as-built data.
Yes, capturing utility data in 3D has become nearly as simple as waving your phone over the trench. Pix4D Catch shown being used. – Image source: Pix4D
For example, Matterport has applications for mobile 3D capture with a phone, like Matterport for Mobile, as well as more sophisticated solutions like the Matterport Pro camera, and Axis. Additionally, if you are looking for higher precision, their Matterport Capture solution can ingest data from other sensors like the Leica Geosystems BLK360 G1 scanner. While their solutions have been adopted mainly for facilities management, they can work for utilities.
When Apple added simplified lidar to some of their devices, it was met with both excitement and skepticism. Noted geospatial blogger Nick Duggan (@drogons8mycat) gave a balanced early assessment, and underscored that while the initial intention for lidar-on-a-phone may have been to improve image capture, the potential was great for broader uses. And this has been realized: give people a new technology and they’ll leverage it in ways not originally imagined.
It did not take long for folks to try the phone-lidar for all manner of applications, including for AEC and asset capture/management. Despite the immediate pushback from folks used to the higher precision of dedicated lidar scanning solutions, tut-tutting that it was not “real” lidar (e.g. not ToF “time of flight”, or pulsed lidar) users have found it useful for creating 3D point clouds (albeit rough ones). But you know what is more imprecise? Yep, utilities that are buried before anyone documents them. Harrumph!
SiteScape has apps for lidar enabled phones and tablets, that can work well for 3D capture of utilities. Image source: SiteScape
An example of a solution developed for the construction segment, but that works well for utilities and asset capture and management, is from SiteScape. An app for lidar enabled iPhones, it is an inexpensive way to get point clouds, and then turn them into many standard output formats, like RCP, E57, PLY, etc. Many users also use the open source CloudCompare for cloud cleaning, cropping, file size reduction, etc. Again, the field capture workflow is quite simple and does not require a lot of experience or training.
But Where is It?
A major challenge in using consumer-grade lidar or cameras for 3D capture is geospatial registration. The GNSS capabilities of your phone will yield positions of 3-50m—1m is a fluke. The inertial sensors in your phone often only serve to (roughly) assist photogrammetric processes to yield a point cloud (if at all, depending on which approach is taken).
You can have a rough 3D model that holds reasonable precision between features in the same point cloud, but a huge element of “where” is absent. Where does it exist in 3D space? Where in relation to an established datum? Where in relation to other infrastructure? I’ve been handed point clouds of utilities that have no orientation, and only a single position provided that tuned out to be tens of meters from the actual location. Sorry, you can’t just “drop as pin” when you are trying to avoid hitting a water main….
Some practitioners have put marks next to the trench, and shot those with a survey-grade GNSS rover, to accommodate the reregistration of the point cloud, subsequent meshed models, etc. This means more gear, more skills, and extra steps. Can the phone do it? Yes, with a little assist.
The viDoc is an RTK rover add on for phones and tablets that enables precise georegistration of captured 3D data. – Image source: Pix4D
Pix4D has taken the initiative to build an add on for mobile phones and tablets that is a fully functioning RTK-enabled GNSS rover—the viDOC, that you attach a phone or tablet to. Not quite a surveyor’s rover, but by using corrections via NTRIP from a base or real-time network (RTN), it can deliver precisions in centimeters. It georegisters the 3D data captured by the sensors/app on the phone. Pix4D has long been a leader in many aspects of 3D capture; initially for the booming UAS segment, and now their Pix4D Catch and viDoc solutions are a welcome terrestrial addition.
Other 3D capture solution providers have also addressed georegistration; there are always many options to explore, and new ones pop up all the time.
An Even Bigger Challenge
Yes, there are now many options for 3D field capture, and these have become simple and affordable enough that just about anyone can grab that geometry while the pit or trench is still open. But what do you do with the data?
Everyone that has developed these easy-capture technologies provides some manner of workflow for the data, mostly in the cloud as many have you send the images/lidar to the cloud for processing into point clouds and/or meshed models. Everyone has a viewer; this is encouraging and provides a way to share the data with others. This is good if an enterprise, a utility, or city has settled on a solution that can host their captured utility data in an easily accessible portal. These hosted portals have become quite sophisticated and can ingest or reference other geo data, like GIS themes, to seek to build a one-stop-shop or digital twin. Yet this often means a layer of data management skills and experts. This is also changing.
Easier Data Management
Australian asset management software firm Skand has been providing solutions for captured data globally for many years, and has received international acclaim. They began with a focus on AEC inspection but have expanded to encompass asset management. In recent years, their approach has changed to embrace the idea that simplicity leads to broader implementation.
“We spoke with more and more surveying companies and digital engineering companies,” says Skand founder Brett Chilton. “And we started to see a bit of a theme around the fact that they often do not understand that they are really capturing very rich data, but simply delivering it to a client. And we asked what the client doing with all the data.” What they found out was that this rich spatial data was being limited to the domain of technical people, and that anyone outside of that realm may never get a shot at it. Chilton and his team viewed this as a tremendous, missed opportunity; “It was an opportunity for a firm to come along and create a window into that world, for non-technical users,” says Chilton. “But it had to be something on a level that I could hand to my Dad.”
Meaning no disrespect to his dad, or anyone else’s, Chilton explains that it is about building a user experience that requires no special knowledge. “I couldn't just give it to my dad and say, ‘Hey, have a look at this really cool 3D space we're building’… you know, too many buttons. And before you know it, he'd be handing it back saying, that's cool, but no thanks.” His is true even within enterprises, utilities, cities, etc.; no matter how valuable that an application could be for asset managements, it will founder if it is not widely adopted.
“Survey companies, they go out and they capture point clouds, they do a bunch of feature extractions,” says Chilton. “And often then they put something in a 2D drawing or PDF, and they give it to the client as the deliverable. But our whole thing is ‘what happened to the point cloud?’ And how would that not be beneficial to others besides those who just wanted limited data in 2D?”
Skand’s viewer for multiple types of 3D data. – Image source: Skand.io
So, Skand made a pivot a few years ago to get more 3D data types into the platform: photos, more types of photogrammetric meshes, point clouds, linework, GIS data (e.g. shapefiles), and more. When it comes to underground utilities, Chilton sees this as a prime opportunity to add to this kind of “infrastructureverse” (OK, I made up that term). “People are opening up the ground and putting stuff in it, and using iPhones to capture that,” says Chilton. “We provide a place to put that data, and ways to access it and share it that is just a simple as operating the phone.”
In their applications, you can do measurements, markups, layer on more data, generate reporting, and more. And if you want to share the data with others, or just part, you can select which layers and area and send it to them via a text and they can visualize and navigate around in it. While elements of what they offer are not completely unique, what Skand has done with their viewer and analysis solutions exemplifies what I’m trying to convey: storing, managing, and sharing the data needs to be just as simple as the new ways to capture it. If 3D reality capture and data accessibility does not reach the every-person level, we are not going to solve underlying asset management issues.
Click
Such tools are rapidly being adopted, but not quite yet at the levels that can have substantive impact. Yes, as-built surveys of underground utilities are required in some jurisdictions, but the cost and time involved in legacy surveying methods has seen others balk at mandating this. Plus, even when it is required, the data may end up in labyrinth of record keeping, sometimes becoming dark data that can be almost harder to find and retrieve than digging a new hole.
The above examples are not any kind of endorsement, but such solutions, and others like them, could be a path towards better underground utility management. So, next time you are standing next to a pit or trench full of utilities, for heaven’s sake, have someone take the phone out of their pocket and document it!
Gavin Schrock is a licensed surveyor and geospatial technology writer based in the Pacific Northwest. He is also a consulting editor for GoGeomatics.ca
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