WHITE PAPER Terrestrial LiDAR Harnessing the Power of Big Data for Asset and Facility Management Patrick Crawford Team Leader, Geospatial Systems SHAFER, KLINE & WARREN
Executive Summary Terrestrial LiDAR is an optical remote sensing technique that has proven to be a powerful surveying tool. With the ability to capture up to a million 3D measurements per second, LiDAR is extremely useful for quickly obtaining precise spatial data to inform engineering and design. By understanding how LiDAR works and how to apply it to your facility, you can ensure your scan project maximizes efficiency while delivering the most value. Facility data from a combination of terrestrial LiDAR and survey control can offer an array of deliverables and inform projects throughout a facility s lifetime. By providing extensive spatial information for a variety of applications, terrestrial LiDAR offers a significant return on investment through resources such as 3D models, survey base maps and 360 degree panoramic images. Above all else, these advanced resources can be delivered with potential cost savings over traditional survey. Understanding LiDAR Scanning and its Precision LiDAR, which stands for Light Detection and Ranging, is an optical remote sensing technique that uses a laser to measure the surface of an object or environment. The power behind terrestrial LiDAR scanning is its ability to harvest enormous amounts of 3D measurement data from a site. New high-definition scanners can gather up to one million points per second, which translates to more than 100 million measurements from a single scan station in only a few minutes. These measurements are immediately digitized and stored onboard the scanning instrument. 2
Measurements from a LiDAR scanner are line-of-sight, so scanning can only measure the surface of objects that are unobstructed from the view of the instrument at a given scan station. Measurement data on structures inside a wall or below ground cannot be obtained using terrestrial LiDAR scanning. However, during a scan operation, multiple scan stations from different vantage points can minimize blind spots and shadows, and buried utilities can be located and documented using traditional survey methods. 4K imagery and dense scan data are collected from the same vantage point and integrate seamlessly to allow for easier interpretation of the data. While the LiDAR scanner must be able to see the structure it is measuring, it does not need to be able to physically touch the structure or object, which allows it to scan and obtain precise measurements on objects and structures that are difficult or dangerous to reach. After completing several scan stations, the scanner registers the measurements by using common targets to precisely link the scan stations together, creating a comprehensive 3D point cloud of everything scanned at the site. While targeted measuring in traditional survey is very accurate, terrestrial LiDAR scanning provides hundreds of millions of data points, including untargeted measurements, which allows for the precise relative measurement of scanned objects. The addition of highly accurate survey control turns those data points into survey-grade coordinates. Survey control is then able to pinpoint where each object is within a room or facility, and likewise its position in the world. This allows for measurements to be duplicated with both accuracy and precision. After the scanning is complete, contractors working on a facility can locate a position by extracting coordinates from the point cloud. 3
Not only does survey control enhance LiDAR ACCURACY PRECISION by tying accuracy to the precise scan data, The degree of VS but LiDAR can also enhance the accuracy correctness of a and precision of survey data. For example, measurement if one were finding the center of a an object as part of a project, the scan would capture thousands of data points on the object from which the precise center could be calculated rather than in traditional survey where the surveyor would attempt to take a single measurement to the center of the object. The vast amount of data provided by LiDAR P Precision O Accuracy O Precision P Accuracy P Precision P Accuracy scanning helps to reduce the possibility of human error and the reliance on one or few measurements. Quite simply, the volume of data that LiDAR delivers allows for the use of advanced mathematical analysis to enable improved decision-making through better information and insights. What LiDAR Can Deliver How close to each other or repeatable the measurements are Following the completion of scan operations, the data is registered to create a point cloud. The point cloud is registered to survey controls, which makes it the most precise and accurate survey record of the subject environment. There are numerous valuable deliverables that can be derived from the point cloud, and while the following are some of the most common deliverables, we have yet to find a limit to the applications and outputs from the point cloud as the technology and use cases continues to evolve. 3D Models One of the most-used deliverables that highlights the capabilities of a LiDAR scan is a 3D model. It provides three dimensional visualization of the subject matter and its environment, which is especially helpful when documenting complex environments, such as power, plant and marine (PP&M) industry facilities with extensive piping that would be difficult to understand in a two-dimensional plan view. The 3D model is a scaled digital replica that enables you to see how things are built, including where 4
pieces of equipment are in relation to each other. To collect and visualize all this information in the past, one would need to do a topographic survey, take photos and hand measurements and complete hand-drawn sketches of a complex system. This would be time consuming and still only produce several two-dimensional representations of a three-dimensional object or environment. Conversely, the 3D model is more than just a visual point of reference. It offers practical depth and perspective that can be used to inform any engineering work on the facility or site. For companies in the oil and gas industry that are often purchasing and selling assets with limited information, these 3D models serve as convenient and comprehensive as-built documentation of an asset. From the 3D model, companies can perform retrofits, schedule maintenance and determine whether their facilities meet regulations. Survey Base Maps Traditionally created from a topographic survey, a survey base map consists of building and utility locations and ground contours. These maps are the basis for any civil engineering project involving grading, elevation, site planning or drainage. The survey base map created by LiDAR scanning is delivered in the same AutoCAD file that would come from a topographic survey; however, LiDAR speeds up the process, and the survey base map becomes just one of several deliverables from the project. The intensity map (left) and TruView of a well pad produced by a LiDAR scan. The user can traverse the site in either view, take site measurements and obtain coordinates. Users are also able to do a virtual walkthrough of the site. 5
Digital Elevation Models (DEM) and Raster Files DEMs and raster files are GIS data sets that show a model of the elevations of a particular area. Typically, these cover large land masses, such as an entire county. The DEMs produced by a terrestrial LiDAR scan cover a much smaller area and allow users to create contours, view site elevations and complete site analysis using GIS. This freedom to create and visualize contours is ideal for more analytical applications as opposed to design applications that would be done in AutoCAD. Additionally, this GIS data set can also be used for queries, averages and other geospatial analytics. 360-Degree Panoramic Images Utilizing Leica TruView, the LiDAR scan outputs a 360-degree panoramic image, similar to Google Street View of the area scanned. Clients can then pan around within the image and inspect the site almost as if they were there without being onsite. Within the TruView, you can take accurate measurements of objects and distances between structures without having to physically be on-site. If using traditional survey, process and instrumentation diagrams would rely on hand-drawn sketches. LiDAR is able to create a detailed diagrams of valve sites, such as this one and eliminates the need for sketches. Process and Instrumentation Diagrams (P&ID) P&IDs are schematic drawings that illustrate exactly how various pieces of equipment work together in a system or process.. In the energy industry, this information is used for compressor stations and electrical structures to view and analyze how the system functions. Often, this is part of the as-built process to document how the current system is set up and it requires an engineer to complete an onsite walk-through. The scan and TruViews allow the engineer to participate in a virtual walk-through. For future adjustments or expansions, the P&ID informs what directions valves need to go, what can be turned off, and what realignments are necessary in order for the system to continue to function. This CAD diagram illustrates three scan stations oriented around a valve setting. The scanner uses the three targets in the diagram to register the scan stations to one another. 6
Volumetrics LiDAR scanning can be used to measure the volume of something, whether it be a stockpile such as sand or coal, or an empty pit or bunker. By scanning at different intervals, one can determine how quickly the volume of something is expanding or contracting. This application is often used to monitor landfills to determine how quickly they are filling and retaining walls to see if the wall is performing as designed.. Effectively Leveraging LiDAR Efficiency and effectiveness are of the utmost importance when managing interconnected facilities and infrastructure. Each of the aforementioned deliverables support this effort by providing convenient access to comprehensive information to inform engineering, site work, maintenance, upgrades, expansion and renovation. Additionally, LiDAR s ability to capture an immense amount of information at high speeds enhances its value for these applications, which is why it is so important to clearly and completely define the scope of work for a LiDAR project. While there is a large amount of collateral data captured during the process of a terrestrial LiDAR scan, the data collection can be targeted based on the goals of the scan. Obtaining higher precision and a more comprehensive scan of a facility can take more time, so identifying primary project goals and areas of interest ensures the scan provides the most critical and valuable information. For example, if a project at a facility required that a connection be made to a specific flange at one end of the site, the scan would focus on getting clear documentation of that detail, and scan positions would be chosen based on the location and views of that flange. Likewise, if an owner were scanning wind turbines as part of an asset inventory, the goal would be to take measurements from the base up to the top of each turbine. However, if the goal was to check for necessary maintenance, then the scope of the project would focus on the blades or the base where the turbine is spinning. Another way the project scope can affect the scan is by dictating which field workflow is used. Typically for scan projects covering a large space, a free-station workflow will be used. As referenced earlier, this involves putting out several temporary targets, then using those temporary targets to triangulate the position of the instrument. However, recently we were asked to scan 39 small sites within a compressed 7
timeline, which meant we had to adapt our typical workflow. In this case, after setting survey control, we used the scanner to traverse through the site without the temporary targets. This is more similar to the typical survey practice of traversing through a site and is a little bit faster, but might not be best suited for projects requiring high-level of detail for specific spots or very large spaces. Nonetheless, it is a good demonstration of how we are able to adapt our technical approach based on the needs and expectations of a client. What Makes LiDAR Worth It When investigating the adoption of new technologies, cost is always an important consideration. In the case of LiDAR, the key considerations that justify its cost are improved decision-making, time efficiencies and employee safety. Terrestrial LiDAR provides a huge amount of information that can be used time and again to make more informed decisions about critical maintenance and operational needs. This has direct benefit to operational efficiency and quality of work. For example, when collecting traditional survey data for a project, the surveyor takes specific measurements as needed for the project scope. This can mean that if a facility has multiple projects over several years, it could require a separate survey for each project. However, the mass harvesting of data that comes with LiDAR scans can be applied to multiple projects within a single site. As a Measurements and coordinates on a remote site can be obtained through TruView Global. This software also allows for virtual site walkthroughs. 8
professional survey firm, SKW stores and maintains all the data collected via LiDAR or traditional survey. In the case of LiDAR, there have been several cases where a single LiDAR scan of a site has been used for multiple projects. And lastly, once the information is on-hand, your staff and contractors are less reliant on site visits to obtain the most basic information about assets or facilities. This represents real benefits in terms of cost savings and improved safety. For example, mobilization costs, which include the travel to and from a job site, can make up as much as 30 percent of the project budget. This makes return visits a costly, inefficient use of the project budget and personnel. Furthermore, the measuring and documentation that would take a week to obtain using traditional methods can be completed in a day using terrestrial LiDAR. Couple these cost savings with the lower risk profile of having fewer people in the field doing this work and LiDAR becomes a compelling, if not necessary component of any new build project or O&M program. Case Studies in LiDAR s Value Recently, we completed a scan of a 1.5 acre natural gas sales point that included above-ground piping, instruments, valves, fittings and tanks. The scan scope was to establish survey control, and scan and document all above-ground features as part of a pipeline integrity management project. The scan By leveraging LiDAR scanning allowed SKW s integrity management team to take for this project, the midstream site measurements and assess the facility without company s cost was nearly additional site visits. We located the underground 40 % piping, and photographed and documented the pipe less and included specifications. The scan took six hours and obtained 250 million measurements. The total field cost was 75 % less than $2,500, and the deliverables included the point cloud, TruViews and photographs from every fewer man hours. scan station. 9
To obtain similar data for the project using traditional survey, measurements of all the above-ground fittings would have to be taken with a tape measure, and the above-ground features would have to be sketched. Additionally, photographs would be taken, underground piping located and pipe specifications documented. The total estimated field time for this would be 24 hours, with a field cost of approximately $3,500. The scope would be limited to several hundred measurements taken with manual tape measure, and deliverables would include field notes, hand sketches and GPS shots. By leveraging LiDAR scanning for this project, the midstream company s cost was nearly 40 percent less and included 75 percent fewer man hours. Additionally, the deliverables are digital and include millions more data points, three-dimensional views and panoramic photographs to inform engineering, maintenance and expansion of the site for years to come. In another case, a single LiDAR scan of a natural gas compressor station was used on six additional operations and maintenance projects. Based on each of these projects requiring at least one day of field work if the client had used traditional survey, the reuse of this single LiDAR scan saved the client $46,800 on these projects over the course of three years. Another recent application that highlights the value of LiDAR was a monitoring study on a 60-foot tall segmental retaining wall to check for shifting or movement of the wall. With the LiDAR scanner, our crew established ground control and scanned the wall from two stations. Twice a year, we revisit the site with the scanner, check ground control for movement and rescan the wall. By comparing scans sequentially, we are able to determine if the wall is moving and pinpoint where its moving. This data is then used by structural engineers to assess the wall s integrity and determine if any modifications or reinforcements are needed. By using LiDAR scanning for this project, we are able to view and analyze the entire wall from the ground without having to scale the wall. The monitoring efforts determined that the wall was moving significantly, and the engineers placed concrete retention boot to secure the toe of the wall. Ongoing monitoring continues to assess the rest of the structure. This retaining wall scan will be compared to future scans to monitor for settling and movement. 10
If applying traditional survey to the retaining wall project, one would have to mark and measure points of interest (POIs) on the wall. Just as with scanning, the site would be revisited twice a year to check ground control and compare data to determine movement. However, there a several limitations to this approach. The limited amount of data collected inhibits the detail of the analysis, which would be based solely on the POIs rather than data for the entire wall. Additionally, new problem areas would have to be identified in the field for measurement; whereas, the scan captures data on all points on the wall that can be analyzed and assessed after data collection is complete. And last, but not least, the manual inspection of the wall s POIs would increase the safety risk for field personnel by requiring them to scale the wall to inspect, measure and mark each POI. Obviously, this is not a concern with LiDAR scanning, because it is completed from the ground. Conclusion Terrestrial LiDAR is a powerful tool for measurement, as-built documentation, planning and engineering. Understanding LiDAR s strengths and limitations, as well as the benefits of investing in the comprehensive data gathered by a scan, enables owners, operators and field personnel to improve their operational efficiency and effectiveness. Additionally, the ability to utilize an experienced surveying firm to conduct LiDAR scanning and tying the data to survey control allows measurements to be precise and easily recreated by contractors working on a project. It is not uncommon for data from a scan to be used multiple times throughout the lifetime of a facility or building, which increases the value of investing in LiDAR as part of a suite of tools and services used to make more informed decisions. Most importantly, as site projects are planned, designed and completed, terrestrial LiDAR saves time and money for owners and operators as the most precise way to document a complicated environment. Patrick Crawford Team Leader, Geospatial Systems Patrick Crawford is a team leader of geospatial systems for SKW Enterprise Solutions, a wholly owned subsidiary of, Inc. Working closely with engineering technicians, Crawford oversees the collection and analysis of geographic and spatial data to create deliverables that inform engineering and design projects. Crawford also works in the field using the LiDAR scanner as needed. He processes the point cloud data in Leica Cyclone and is experienced using the scan clouds for modeling purposes inside CADWorx. Crawford has presented at national conferences on leveraging LiDAR effectively and he recently earned his FAA certification as a Remote Pilot in Command. 11
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