An Introduction to High Density Laser Scanning

By Donnie Longenecker, MLA, President / Founder of Design Technology Consultants, (DTC) , Instructor, University of Georgia School of Environmental Designn

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Design Technology Consultants, (DTC) is a full service design and design management firm located just outside Athens, Georgia. For the past 12 years, DTC has been involved with the development of large-scale resort / residential and commercial projects throughout the southeastern U.S.

Many of these projects have been in environmentally sensitive areas and have involved requiring the project team to come up with site-specific solutions requiring some “outside of the box” thinking.

Many of these site-specific issues concern the inability of the project team and client to fully understand the three dimensional characteristics of a site. More often than not this difficulty causes final adjustments to be made on site in real time. Unfortunately, these adjustments end up costing time and money during the construction phase. The client must spend additional dollars to pay for site visits, meetings, and or revisions, which could have been avoided had there been a more effective way of fully understanding the site conditions.

High-definition laser scanning is a relatively new technology that enables surveyors to fully capture all the elements of a site and convey it to architects, planners and landscape architects in three dimensions. Over the last 24 months, DTC has formed a strategic partnership to help bring this technology to the mainstream in both public and private sector projects.

This is a point cloud created from a scan of the streetscape in Augusta, Georgia. The city and county are using the data from this scan to help analyze existing conditions and suggest improvements to downtown areas. The point cloud can be manipulated to allow the designer or client to visualize the impacts of removing structures and or vegetations.

A Digital Point Cloud

Laser scanners work by transforming the surrounding environment into a digital point cloud. Just as a cloud is comprised of millions of water droplets, a digital point cloud contains millions of data points. Using phase shift lasers, the scanner records an image and the X, Y, and Z coordinates of each point that it measures. Points are measured in a 360-degree sphere around the scanner, and can be measured as close together as one-quarter inch at a distance of 300 yards. This enables distant or hard to reach items to be accurately measured and recorded.

The trees that surround the building are “sawn off” at a height of six feet in the point cloud to show the effects of the clearing. You can move about the point cloud just as if walking the site in person. Because all of this data is GPS referenced, a tree in the point cloud is at the exact location as the tree on site.

A Historic Building

Recently, DTC worked with its partner to complete a set of as-built drawings for a historically significant building in Georgia. One portion of these drawings involved creating a reflected ceiling plan for a structure that was 30-feet off the ground. Using laser-scanning technology, we were able to produce drawings that had a one-quarter inch tolerance, without ever leaving the ground. Needless to say, this procedure saved the client thousands in surveying and measuring costs over more traditional methods.

This surrounding scan data of a proposed office building in Marietta, Georgia was taken over a period of several months, then compiled using the Cyclone software. Architects were able to insert a model of their proposed office building into the point cloud to determine how their design would work with the surrounding environment. The architects realized several of the views they were expecting to see from the top floors were blocked by adjacent buildings. The decision was made to increase the proposed height by one floor. Using this information, these decisions were realized before the first foundation was dug.

Manipulating the Data

Once the point cloud has been generated, technicians can use Leica’s Cyclone software to manipulate and view the data in a variety of ways. The data can be linked to a GPS coordinate system, and used to create surveys and topographic maps. In addition, Cyclone can be used to create dramatic “fly-through” visualizations of the point cloud data. Recently, DTC and its partner completed an as-built survey of a golf course using nothing but laser scanners and GPS coordinate data. The client received a full set of topographic drawings and a digital model of their site. The following photographs are typical deliverables for this type of project.

The point cloud can be manipulated to allow the designer or client to visualize the impacts of removing structures and or vegetations. The photographs in this column give an example of such visualization. The trees surrounding a building in the point cloud were “sawn off” at a height of six feet to show the effects of clearing. We can then move about the point cloud just as if one were walking the site in person. Because all of this data is GPS referenced, a tree in the point cloud is at the exact location as the tree on site. We have demonstrated this ability to a variety of public and private clients. All of them see tremendous potential for this technology to help study the impacts of clearing on a particular site.

Large-Scale Planning and Visual Assessment

A final use for this technology is in large-scale planning and visual assessment. Point cloud data is being used to study proposed and existing visual impacts on two different sites. A point cloud was created from a scan of the streetscape in Augusta, Georgia. The city and county are currently using the data from this scan to help analyze existing conditions and suggest improvements to downtown areas.

The surrounding scan data of a proposed office building in Marietta, Georgia was taken over a period of several months, then compiled using the Cyclone software. Architects were able to insert a model of their proposed office building into the point cloud to determine how their design would work with the surrounding environment. After studying the visualization, the architects realized several of the views they were expecting to see from the top floors were blocked by adjacent buildings. The decision was made to increase the proposed height by one floor. Using this information, these decisions were realized before the first foundation was dug.

As the market for land development continues to rebound from our current economic condition, profit margins and development budgets will be quite slim. DTC and our strategic partners believe that the ability to make accurate, real time, proactive decisions will be crucial in helping our clients succeed. High definition laser scanning could prove to be a key component in that overall strategy.

Donnie Longenecker can be reached at donnie@dtcinc.biz.