Notes

Embracing Mobile 3D Laser Scanning
"Technology is advancing so quickly that it's slowly replacing the surveyor." These concerns have been voiced again and again as LiDAR scanning becomes more accessible. The most recent 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 seen as a threat due to efficiency should be embraced to ensure that surveying to survive. Land surveyors are increasingly passing up on surveying work because they are not advancing in current measurement technologies. Understanding and appropriately giving an answer 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 are 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 assist survey professionals that led to shedding pounds 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 looked at as another replacement. The continuing future of the surveying profession is still viable if the technology is 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 he encounters this attitude. "Sometimes I hear our customers say, 'Well, the surveying profession is dying and there is no future for all of us.' The need for geo-information is tremendous, and growing; geo-information has to be more up to date, more 3D, more accessible on the internet, and so on. There are not many industries that offer so many exciting prospects."

Understanding the Technology
Technology is continually changing, and so must the surveyor's tools. The finish product is only as effective as the initial field data gathered. TMLS systems measure thousands of points a second whilst travelling at highway speeds. The info gathered are complete 3D images of the space being measured. What used to take months now takes only 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 trained in spatial recognition, virtually walking the site becomes a benefit to the info extraction process. This technique allows the surveyor to extract data in more areas than he would have performing traditional shots every 25 feet.

Accompanying video documentation and digital images allows for an improved QA/QC process through a recorded visual reference. This allows the surveyor to return to the website at the desktop rather than revisiting the field to make additional observations. Combined, this creates a collection of better original survey data for surveyors with added benefits.

Great things about TMLS Surveyors must approach this proven technology as a way 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 method of 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 your client through:
? acceleration of the design 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 data remaining in-house.

Accuracy: TMLS is a proven technology. Evaluations performed at a Caltrans test area specifically made to judge mobile laser scanning systems led to an RMS error of 0.022'. The route chosen was to permit 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 need to expand their horizons by learning multiple software packages for field-to-finish and office computations. There are a variety of new services a traditional surveyor can add to the profession to expand business through TMLS. Surveyors who acquired scanners originally to perform traditional surveys and inspections are carving their 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 complete investigations faster and much more thoroughly, and mere usage of scanner data is keeping them ahead of the competition when bidding for new jobs.

In past times, the airborne industry has documented nearly all overhead line surveys. With mobile 3D laser scanning, wires right down to 3mm in diameter can be accurately located and their heights measured. The info permits calculations of sway and sag of overhead power lines. The price to the client between airborne and mobile surveying is really a drastic reduction. What the "fly-by" replaced in speed from traditional methods, the "drive-by" benefits in cost. TMLS technology, just like the StreetMapper system out of the United Kingdom, can simply be adapted within less than an 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 whatever can be acquired 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 used for homeland security issues and evacuation planning. Colorization of models are benefits to planning boards and marketing city attractions and expansion. City modeling is rapidly learning to be a significant catalyst for data acquisition through technologies such as Google Earth and MapQuest.

Rail construction tasks require reliable survey data. Because of Mobile Mapping Stapleton increasing traffic load, combined with age structure of the rail network, responsible administrations are forced to place the primary emphasis of maintenance activities into projects to make sure 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 is needed in advance to capture basic data for construction planning and preparation. TMLS mounted on a hyrailer minimizes the survey effort to capture the required data along existing railways.

Just a comparatively short driving time is necessary for data collection, while the traffic flow isn't significantly affected. This process 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 and also 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, time consuming, 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 is the most efficient solution to measure various structures and roadway features. Accuracies of better than 1/2" have already been obtained for vertical clearances of roadway structures. It is critically important in oversize route planning. Horizontal clearance measurements must also be maintained. Collecting this data in a normal manner could be dangerous or could cause congestion with work crews subject to serious traffic hazards. Work must be performed during available traffic breaks, which can introduce errors. From a system-wide perspective, clearance information oftentimes is incomplete, inaccurate, and difficult to keep and to access.

Highway surveys with mobile 3D laser scanning are used for maintenance and asset management of road surface and street configurations by identifying concrete spalling and pitting. Construction monitoring can be obtained for forensic identification of rebar placement before a pour. This data allows for 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 obvious that mobile lidar will be the technology of choice ultimately."

These are 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 respond to these technology advancements will remain prior to the concerns of an otherwise seemingly dying breed.

Website: https://landsurveysbristol.uk/best-mobile-mapping-bristol/