When George H.W. Bush was president, he started a campaign called “1,000 Points of Light” to honor individuals and companies that support volunteer-based organizations. Today, 1,000 points of light is nothing compared to the millions of laser light points collected on surveying jobs daily.
That may be a stretch comparison but it does point out the fact laser mapping has become common, especially among the infrastructure crews that build and maintain highways, bridges, and airports. But collecting those millions of light points can be a hassle when you have to do it with a tripod-mounted laser theodolite. Mapping a highway route in 3D that way often requires doing it at night to limit the disruption to traffic.
Now there is a better way. Traveling at normal traffic speeds, the StreetMapper system, a joint development of UK-based 3D Laser Mapping and German guidance and navigation specialist IGI, www.igi-systems.com, Kreuztal, Gernany, captures survey grade data with millimeter measurement accuracy.
A recent project included a section of the main highway that forms part of the coastal link between Perth and Port Hedland in Australia. The StreetMapper system completed the 8.5 km (5.3 miles) survey in a matter of hours without any disruption to other road users and during normal working hours. The verified and rectified point cloud—the millions of individual measurements collected by laser scanners—was then processed to produce string data in conformance with the government’s requirements.
Using vehicle-mounted lasers offering a 360-degree field of view, StreetMapper enables high precision mapping to a range of 300 meters, a capacity of 300,000 measurements per second per sensor and recorded accuracies in independent real world projects of better than 10 millimeters.
Mobile mapping systems can capture highly detailed and accurate data to support rehabilitation projects, as well as the design and layout of new roads. Since such a survey can be done at normal traffic speeds, there is no need for road closures or other safety precautions. Data can then be post-processed into a number of formats including GIS (geographic information system) and CAD (computer-aided design).
And it isn’t just for above-ground purposes. When the earthquake and follow-on tsunami hit Japan earlier this year, StreetMapper technology was used to assess the structural damage caused as well as the effects of soil liquefaction—the loss of strength from saturated soil—which is an important factor in that area where much of the land is reclaimed from the sea.