Using the world’s most accurate mobile mapping system StreetMapper, geospatial engineering company Coastway has completed an as built survey of the final section of the M8 motorway.
Collecting billions of highly accurate measurements in a fraction of the time it would take using traditional survey techniques the resulting 3D models will be compared to the digital road design and will be used as a base line record against, which future surveys can be compared.
Opened on the 28th May 2010 the 41 kilometre M7 Portlaoise to Castletown and M8 Portlaoise to Cullahill section was the last to open and completes the Dublin to Cork interurban route.
“StreetMapper appeared to be the only logical way to complete such a large survey in a timely and cost effective way,” commented Mark Hudson, Director and co-founder of Coastway.
“In all, the actual time in the field amounted to little more than a day during which some 2 billion points were measured. The StreetMapper data was easily tied into our existing work flow which, despite the large volume of data collected, made processing relatively easy.”
Using StreetMapper and working on behalf of the Portlaoise Joint Venture, Coastway mobile mapped both carriageways on each side of the newly constructed motorway, including slip roads, recording as built road levels, utilities and structures. A combination of the StreetMapper data and GPS was used to create a 3D model of the road surface from which cross sections were generated at intervals of 10 metres for comparison with the design at the corresponding chainage. Additional control points along the route were used to tie the StreetMapper data to the site grid contributing to an absolute vertical accuracy of better than 10 millimetres.
The resulting models can also be used as a base line against which subsequent surveys can be compared to check for deformation or deterioration of the road surface, asset management, redesign, bridge clearance, route planning and road marking and signage.
“Simply put, it is not possible to carry out such a comprehensive and accurate survey of a large site like this using traditional techniques alone,” concluded Hudson.
StreetMapper 360, which is a joint development between UK based 3D Laser Mapping and Germany based guidance and navigation specialist IGI, has been specifically designed for the rapid 3D mapping of highways, runways, railways, infrastructure and buildings. Using vehicle-mounted Riegl VQ-250 lasers offering a 360-degree field of view, StreetMapper enables high precision mapping to a range of 300 metres, a capacity of 300,000 measurements per second per sensor and recorded accuracies in real world trials of better than 10 millimetres.
