To keep tabs on its infrastructure, Las Vegas uses the survey-grade ScanStation laser-scanning system offered by Switzerland-based Leica Geosystems AG to gather immense amounts of data about an intersection or projected roadway, or for any topographic surveying task. Fewer than 300 of these systems are in use across the country.
By setting up this unmanned equipment to survey the landscape, the city's three survey crews can quickly (about 30 minutes) and safely (no traditional middle-of-the-street surveying required) gather survey-grade data in a full field of view.
The pulsed laser scanner bounces off each element in its field of view. These thousands of points are scanned each second, and data return to the scanner to “paint” a picture of what it's seeing (buildings, underside of bridges, roads, storm drains, etc.). It collects much more data than a typical laser scanner.
The ScanStation is being used to acquire topography on Las Vegas city streets going through design for repair and rehabilitation. Surveyors also used it to collect topographic information to help design a city park.
Since every surveying task is different, not all tasks are suited for this technology. Where line of sight is restricted by fixed objects, surveyors use conventional techniques.
“About 30% of the topographic surveying we do is being accomplished with the ScanStation,” says city surveyor Alan Riekki. “However, where the instrument has a clear field of view, the amount of time spent in the field collecting topographic data can be reduced by as much as 50% from a conventional survey.”
That, calculated against the daily cost of a field crew, justifies the city's $145,000 investment in the equipment, which Riekki estimates will pay for itself in less than two years.
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