Notes

Embracing Mobile 3D Laser Scanning
"Technology is advancing so quickly that it is slowly replacing the surveyor." These concerns have been voiced over and over as LiDAR scanning becomes more accessible. The newest advance in scanning is terrestrial mobile LiDAR scanning (TMLS). This technology collects survey-grade data at highway speeds and at traditional survey costs, and in the transportation discipline this is a safer method of data collection while reducing risk for the entire project. Nonetheless it has surveyors questioning the longevity of these profession. What is regarded as a threat due to efficiency must be embraced in order for surveying to survive. Land surveyors are increasingly passing up on surveying work because they're not advancing in current measurement technologies. Understanding and appropriately responding to non-traditional ways will significantly contribute to the success of the surveying profession and to the clients you serve.

Changing a Mindset
Historically, improvements in the surveying profession include the use of real-time kinematics (RTK) and global positioning systems (GPS) replacing field crew members. The robotic total station was another scientific invention to aid survey professionals that resulted in slimming down crews. So did the calculator for field trig values and computers for CAD drawings, but eventually they too were accepted and are widely used today. The profession adjusted.


Now mobile 3D laser scanning is developing a new apprehension from an over-restricted view of the profession, although TMLS doesn't have to be viewed as another replacement. The continuing future of the surveying profession continues to be viable if the technology can be used as "another tool in the toolbox." Hans Hess, former CEO of Leica Geosystems, among the major producers and suppliers of both survey field equipment and static laser scanners, says that he encounters this attitude. "Sometimes I hear our customers say, 'Well, the surveying profession is dying and there is no future for us.' The need for geo-information is tremendous, and growing; geo-information has to be more up-to-date, more 3D, more accessible over the internet, and so on. There are not many industries that offer so many exciting prospects."

Understanding the Technology
Technology is continually changing, therefore must the surveyor's tools. The finish product is only as effective as the original field data gathered. TMLS systems measure thousands of points another while traveling at highway speeds. The info gathered are complete 3D images of the area being measured. What used to take months now takes just a few hours in the field. The surveyor or CAD technician can extract the needed top features of this data in the office at the desktop. As the surveyor is been trained in spatial recognition, virtually walking the website becomes a benefit to the data extraction process. This system allows the surveyor to extract data in more areas than he'd have performing traditional shots every 25 feet.

Accompanying video documentation and digital images permits an improved QA/QC process by way of a recorded visual reference. This allows the surveyor to come back to the site at the desktop instead of revisiting the field to create additional observations. Combined, this creates a collection of better original survey data for surveyors with benefits.

Benefits of TMLS Surveyors must approach this proven technology in an effort to solve problems in the field. Many organizations have developed key standards for safety, efficiency, and accuracy, and mobile 3D laser scanning addresses those standards in the next ways.

Safety: Survey-grade road surface documentation at highway speeds improves safety and efficiency for both traveling public and the surveyor in the next ways. It:
? eliminates road/lane closures,
? reduces traffic disruption,
? finishes the project more quickly than traditional methods,
? is a safer approach to data collection, and
? keeps the surveyor out of the red zone.

Efficiency: Because in-house surveyors supply control and check shots through traditional methods, efficiency is increased,and those benefits could be passed through to the client through:
? acceleration of the look project schedule through faster field data collection,
? deliverables created through in-house technicians,
? data designed for extraction, when needed, how needed, where needed, and
? control of the info remaining in-house.

Accuracy: TMLS is a proven technology. Evaluations performed at a Caltrans test area specifically designed to evaluate mobile laser scanning systems led to an RMS error of 0.022'. The route chosen was to allow companies advanced in mobile laser scanning technology an independent evaluation against CalTrans total station collected points.

Implementing TMLS
Many surveyors have mastered only one way of performing surveying operations, and they have to expand their horizons by learning multiple software programs for field-to-finish and office computations. There are a variety of new services a traditional surveyor can truly add to the profession to expand business through TMLS. Surveyors who acquired scanners originally to perform traditional surveys and inspections are carving their very own niche in the market through accident reconstruction surveys. Companies which have been doing forensic work for years have discovered that laser scanning enables them to perform investigations faster and more thoroughly, and mere access to scanner data is keeping them prior to the competition when bidding for new jobs.

Previously, the airborne industry has documented nearly all overhead line surveys. With mobile 3D laser scanning, wires right down to 3mm in diameter could be accurately located and their heights measured. The data allows for calculations of sway and sag of overhead power lines. The cost to your client between airborne and mobile surveying is a drastic reduction. What the "fly-by" replaced in speed from traditional methods, the "drive-by" added benefits in expense. TMLS technology, like the StreetMapper system from the United Kingdom, can easily be adapted within less than one hour to vessels providing high-resolution coastal land surveys of upland features, including dunes, beach cusps, scarps, and vegetation. The 3D laser scanning resolution far exceeds that which can be obtained through traditional surveying methods. This enables for surveys of unprecedented detail.

Rapid data acquisition through TMLS enables the generation of 3D city models to be utilized for homeland security issues and evacuation planning. Mobile Mapping Lawrence Weston of models are added benefits to planning boards and marketing city attractions and expansion. City modeling is rapidly becoming a significant catalyst for data acquisition through technologies such as Google Earth and MapQuest.

Rail construction tasks require reliable survey data. Due to highly increasing traffic load, combined with the age structure of the rail network, responsible administrations are forced to place the main emphasis of maintenance activities into projects to ensure quality, safety, and sufficient traffic capacity. The negative influences of maintenance tasks need to be kept as small as possible. This is a lot more important for the necessary substantial engineering/survey work that's needed in advance to capture basic data for construction planning and preparation. TMLS installed on a hyrailer minimizes the survey effort to capture the mandatory data along existing railways.

Just a comparatively short driving time is necessary for data collection, as the traffic flow isn't significantly affected. This approach reduces both costs and safety risks.Three-dimensional airport surveys captured by TMLS empower engineers and land surveying crews with scan data of runway surfaces, building footprints, measure distance, sign identification, and locations along with survey terminals, taxiways,and aprons, all without disruption to air traffic.

Automated permitting for truck routing for bridge heights and clearances by traditional survey methods is costly, frustrating, and presents difficult in managing the changing data because of continued highway construction resurfacing projects. Obtaining survey-grade accuracy for bridge heights and clearances at traffic speeds may be the most efficient solution to measure various structures and roadway features. Accuracies of much better than 1/2" have been obtained for vertical clearances of roadway structures. It is critically important in oversize route planning. Horizontal clearance measurements must be maintained. Collecting this data in a traditional manner can be dangerous or could cause congestion with work crews at the mercy of serious traffic hazards. Work should be performed during available traffic breaks, that may introduce errors. From a system-wide perspective, clearance information oftentimes is incomplete, inaccurate, and difficult to maintain and to access.

Highway surveys with mobile 3D laser scanning are employed for maintenance and asset management of road surface and street configurations by identifying concrete spalling and pitting. Construction monitoring can even be obtained for forensic identification of rebar placement before a pour. This data permits complete surface contour capabilities of road crowning and rutting measurements.

Mark Coon, LS, a geospatial manager at Erdman Anthony, says, "We currently use Terrestrial LiDAR on highway and bridge surveys for the NYSDOT, and it's really obvious that mobile lidar is definitely the technology of choice eventually."

These are just some of the ways the surveying profession can enhance their services using TMLS as another tool within their toolbox. Surveyors who understand and accurately position themselves to react to these technology advancements will stay prior to the concerns of an otherwise seemingly dying breed.

Here's my website: https://parrish-bartlett-2.blogbright.net/faqs-about-simultaneous-localization-and-mapping