The first article of this series onlaser scanning (May 2004)characterized this technologyas an “ultra-fast, high-defini-

tion, reflectorless survey” that’s proveneconomically beneficial for certaintypes of sites, structures, and projects.The most recent article described thetypes of “sites and structures” bestsuited for this technology:• Complex geometry, surfaces• Relatively clear of vegetation and/or

many stationary visual obstructions• Lots of detail, congested, tight fits• Far away or difficult to access• Limited in size/area• Sites that are in active, continuous use• Hard-to-reach or delicate surfaces• Unsafe to occupy

One or more of the above bulleteditems will be checked for virtually everyhigh-definition survey. Note that a dis-tinction is made here between types of“sites/structures” and types of “proj-ects.” “Types of sites and structures”refers to their physical characteristics (in-cluding location), e.g., a site with com-plex geometry that’s located very far fromthe survey office. “Types of projects,” onthe other hand, refers to the business as-pects of a project, for example, a projectthat may have to be done on a very fast-turnaround basis. This article delves intowhat types of “projects” are the best can-didates for high-definition surveys.

Project Business Factors That

Favor Scanning

Project business aspects of projectsthat benefit most from high-definition

surveying are usually those that benefitfrom high-density data and/or from ultra-fast measurement. Often, such projectshave one or more of the following busi-ness characteristics:

Geoff Jacobs

HIGH-DEFINIT ION SUR VEYING: 3D LASER SCANNING

What Kindsof Projects

Benefit Most?

Bad as-built data can ultimately lead to longer plant shut-downs.

• Confidence in the as-built or as-is data is important

• Potential to re-use the data later• Fuzzy scope or expected scope changes• Potential for multi-discipline use of

the as-built data• Fast turnaround needed• Short window to collect data

Each of these is discussed further be-low, with examples given.

Confidence in the as-built data is

important—This aspect of high-defini-tion surveying may ultimately have the

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HIGH-DEFINIT ION SUR VEYING: 3D LASER SCANNING

High-definition surveys can aid forensic investigations.

Original garage scan was re-used for follow-on client needs.

most profound impact on surveyors andother measurement professionals. At arecent conference, I heard a ProjectManager for a civil/survey company talkabout a high-definition survey projectthat his company had completed for astate DOT. Scanning had been used on anumber of complex overpasses and in-terchanges for a major highway im-provement program in a large metropol-itan area. The survey company ProjectManager explained that the biggestbenefit his DOT client had cited to himfor using their laser scanning serviceswas the client’s “ability to rest peaceful-ly at night,” knowing that the data thathad been collected in these challengingareas was correct. In this case, the costof the high-definition survey was alsoless than the cost of a traditional sur-vey, but the client focused on the addedconfidence aspect.

Staying on Schedule

Confidence in survey results is some-thing that many professionals take forgranted; but it’s also something thatmany don’t take for granted, especially ifthey have been burned by errors/ omis-sions and the consequences were large.Plant as-built surveys are another exam-ple where this business considerationapplies. The scenario is this: a plant pip-ing designer needs to route some largepiping through an already congestedarea. The new piping is needed becausenew equipment is being installed to in-crease plant capacity. To accommodatethe installation of the new equipmentand piping, the plant must be shutdown, say for 72 hrs. If the pipe routingdesign is bad, there will likely be costly,unplanned field welding and rework and

the schedule for putting the plant backonline may be in jeopardy. Even a one-day delay in getting the plant back on-line could cost the plant owner $600,000in revenues.

This is not a fictional example. Thiswas a real case for one of laser scan-ning’s early, landmark projects (“3DLaser Scanning Helps Chevron RevampPlatform,” Oil & Gas Journal, April 30,2001, Floyd H. Sanders). Piping/CAD de-signers had already done a manual as-built survey of the platform. The as-builtdrawings had been used for design andfabrication of new piping “spools.” TheChevron Project Manager, however, hadprevious bad experiences with thesetypes of retrofits and wanted to reduceproject construction risks. He used con-tingency budget money to scan the plat-form area of interest to double-checkthe proposed design prior to actual con-struction. The 10% contingency budget($200,000) existed precisely because ofChevron’s familiarity with the risk in-volved in plant retrofits. The high-defini-tion survey was money well- spent. Itcaught several key errors and omissionsin the manual as-built survey; pipespools were then corrected at the fabri-cation shop. Overall, the actual installa-tion went faster and smoother thanplanned. More importantly, it reducedschedule risk. By investing roughly$50,000 (at the time) in laser scanning,the project was completed $120,000 un-der budget and the platform went backonline 32 hours ahead of schedule,earning the owner an additional$850,000 in revenue!

The above example is not unusual.High-definition surveying is being in-creasingly used for plant retrofit projects

as a means of risk reduction, both forcapital risk (to minimize rework costs)and schedule risk (i.e., that the plant/fa-cility will be out of service longer thanplanned). Thus, it’s often used on “criti-cal path” items, i.e., ones that impactproject schedules and availability of thesite/plant/facility/asset. Likewise, it’salso being used on new construction(buildings, plants, infrastructure proj-ects) as a QA check on critical structuresto make sure that they’ve been installedor fabricated correctly. The notion hereis to ask the question, “What if thisthere’s an error in the geometry of theconstruction? What would be the down-stream consequences?” The bigger theconsequences, the more suited thathigh-definition surveying is to the task.

Another increasingly common busi-ness example is the use of high-defini-tion surveying for forensic investiga-tions in which large financial settle-ments are at stake. One organizationthat specializes in this area, PrecisionSimulations Inc., has already used laserscanning on a dozen such cases. For sit-uations in which the physical character-istics of the site/structures lend them-selves to it, a high-definition survey canprovide compelling forensic evidencethat drives settlements more quickly.

Potential re-use of data—A user re-cently told me about a project that, onthe surface, was relatively simple: a fewpoints were needed to map the outlineof an existing parking building at groundlevel. The survey project manager elect-ed to use laser scanning because he wasaware that further development was be-ing planned adjacent to the building. Hethought the scan data might be re-usablefor subsequent requests on the project.

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T-REX highway stack scans were re-used for column as-builts.

Column, drain, and spout modeled fromoriginal T-REX bridge scans

He was right. Over the next year, theproject’s engineers/architects came backto his company with two additional, sep-arate survey requests for the same build-ing/area, including cross-sections at fourelevations. The survey company was ableto provide the client with the additionaldata from the original high-definition sur-vey without returning to the site. Theroughly $3,000 original survey requiredonly $3,500 in additional costs to theclient to provide the additional deliver-ables almost immediately. Done tradi-tionally, the client would have incurred anestimated additional $11,000 in fees andhad to wait longer for survey drawings.Over time, the client caught onto the factthat high-definition surveys often containdata needed later in a project; as a result,the client has specifically asked for laserscanning on subsequent projects.

Another example: on the T-REX high-way expansion project in Colorado, anumber of bridges had been laserscanned by David Evans & Associates(see Professional Surveyor, January2004) to support road and bridge design.One of the scanned areas was a highwaystack. A light rail system was planned tothread through the stack. Many monthsafter the original high-definition surveyshad been completed, the client request-ed additional information about thegeometry of the structural supports in thestack. Designers needed to ensure thatthe rail tracks would not be too close tothe existing columns. DEA found that accurate column geometry had been

captured in the original high-definitionsurveys, eliminating the need to send acrew back to the site. When DEA lookedclosely at the data they saw several inter-esting things: these were facetedcolumns with drainage piping that ran thelengths of the columns. Further, they no-ticed that several drain spouts extendedhorizontally from the pipes! DEA was ableto accurately model the columns, thedrainage pipes, and the spouts to giveprecise as-built information to the client.Over time, the value gained from thesetypes of projects has made many clients“believers” in the technology.

Fuzzy scope, possible scope changes

—This business characteristic could beconsidered a variant on the “potential re-use of data.” Projects that involve scopechanges during the project or projectswhose initial scope is not clearly defined(the client may still be unsure about cer-tain aspects of the project) have benefit-ted from high-definition surveys. The rea-son? The scanning executed for the origi-nal project scope may well provide datathat can be re-used if there are scopechanges. The offshore platform project ref-erenced above, in fact, is a good example.During the project, piping designers decid-ed to make some additional improve-ments to the platform. These scope-change decisions were made after the

scanning had been completed for the orig-inal scope. Designers, however, found thatthe geometry data they needed for theiradditional design work was already cap-tured in the original high-definition survey.No extra trips to the platform were neededand designers received their data sooner.This benefit has become commonplaceover time.

Multi-discipline use of the data—

Some projects involve a number of disci-plines that need geometric data fromthe same site. Perhaps each needs dif-ferent data. Such projects are often ex-cellent candidates for laser scanning. Acommon example of this would a facilitythat is about to undergo a refit. As-builtdata may be needed the MechanicalDept. (e.g., piping and flange informa-tion), the Electrical Dept. (cable tray lo-cations), HVAC, Structural, ConstructionEngineering, etc. Historically, one de-partment might send people to the site(or retain surveyors) to measure what itneeds; another department might sendits own staff (or retain surveyors) tomeasure what it needs, etc. With a high-definition survey, a single trip to the sitecan provide a single source of as-builtinformation that each discipline candraw on for its needs.

Plants and facilities are not the onlyexample of this. In the UK, a very

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HIGH-DEFINIT ION SUR VEYING: 3D LASER SCANNING

Railway scan data can be used by multiple disciplines.

reflectorless feature can provided addedvalue when as-built data is neededquickly. A good example of the latterwas a survey of a rail/roadway crossing,including extensions of track in each di-rection. Typically, securing permits to oc-cupy the track to survey it would take sixweeks. The client, however, needed theas-built drawings in two weeks. The civ-il/survey service provider used laserscanning to survey the RR crossing andtrack extensions by simply setting upthe scanner outside of the zone forwhich permits were needed.

Another example where fast turn-around was needed was a plant retrofitconstruction project that had run intofit-up and interference problems during

construction. The project was inthe midst of an extensive delaywhen the Project Managerschose to “bring in the scanner”to curtail any further construc-tion delays.

Short windows to collect da-

ta—Sometimes there are verylimited time windows to access asite or facility to collect data. Ex-amples include surveys of tun-nels, railroad tracks, airport facil-ities, or plants that temporarilyshut down for maintenance.

Crews have to get in and out quicklyand collect as much data as they canduring those shutdowns. I have evenheard of examples for automotive man-ufacturing plants where as-built datahad to be collected during assemblyworkers’ formal breaks. In many cases,laser scanning can be a viable option.The ultra-high speed capture of phase-based (i.e., continuous) scanners, inparticular, can be especially beneficialin such cases.

Site Characteristics + Project Business

Characteristics Combined

When organizations are consideringhigh-definition surveying, the physicalcharacteristics of the site or structureare often the first driver. This is usuallywhere cost savings related directly tothe as-built survey itself are first identi-fied. The second set of project/businesscharacteristics is an important addition-al consideration. If the data were inaccu-rate or incomplete, how large would theconsequences be? Can the data be re-used for subsequent needs? Can the da-ta be shared by other disciplines? Howquickly is the data needed? These ques-tions are an important complement tothe question of initial survey cost.

Summary

Laser scanning can offer cost, schedule,and other advantages for certain types ofprojects. The business characteristics ofsuch projects have been described and ex-amples have been given for a wide range ofpotential projects. When a project’s busi-ness aspects are considered along with thephysical characteristics of a site and/orstructures, the new assessment can lead tolaser scanning being determined a pre-ferred method.

Geoff Jacobs has beenemployed by Cyra Tech-nologies Inc. (recentlyre-named Leica Geosys-tems HDS, Inc.) since1998. He currently actsas Senior Vice Presi-dent, Strategic Market-ing. He is also a Con-tributing Writer for the magazine.Scanning allowed fast turnaround of maps for this

intersection.

successful survey company has taken ad-vantage of this in the rail industry. Thesurvey firm found that several differentdepartments within the railroad authorityclient were each dispatching surveycrews to the same site to measure differ-ent aspects of the site. One disciplineneeded track information; others neededinformation about overhead lines andsupport structures, others about the plat-forms, and still others about signalingand signage. By understanding the needsof each department, the service providerwas able to gather all of the informationneeded by the various departments froma single high-definition survey.

Fast turnaround is needed—Laserscanning’s ultra-fast data capture or its

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