SAM O. HIROTA, INC.
HONOLULU, HAWAII
3D CITY SCANNING
"We have figured out how to generate city wide scans from the sidewalk using our color LiDAR scanners." Dennis I. Hirota, PhD, PE, LPS
3D Full Color City Laser Scanning
Sam O. Hirota, Inc.'s ambitious project seeks to 3D document as much of the city of Honolulu's streets, sidewalks, and buildings as possible using a small crew and company owned and maintained 3D laser scanners. Over the course of less than two weeks of scanning, the crew captured approximately 1.15 million square meters and a perimeter of 5 thousand meters from more than 1,000 scan positions. The RTK GPS registration software generated a 5mm grid of the 8 billion points, with each point having a geospatially correct x, y, and z position.
The resulting 8 billion-point point cloud encompasses parts of Chinatown, major areas in downtown Honolulu, the Capitol district, Federal and State office buildings, sections of the projected new rail line, City Hall, Police Headquarters, the Sam O. Hirota, Inc. building, and historic Thomas Square along major thoroughfares King Street, Beretania Street, Ala Moana Boulevard, and Nimitz Highway.
To visualize the giant point cloud, SOH President Dennis Hirota compressed the original 155.69 GB file into a more manageable 44.4 GBs. In this format, it can now be shown on an iPhone or iPad, creating compelling and easily maneuverable flythroughs of the city. Many people think that because three-dimensional views can be seen from the air, like the ones above and right, a drone must have captured the scene. But all scans were taken from street-level. It's the unique ability of scanning that gives all of the points x, y, and z positions, allowing views from any height and direction.
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Making visualization more useful to those tasked with analyzing road conditions, signage, accessibility, etc. is SOH's ability to remove cars, people, and other moving objects from the point cloud. Additionally, speed of capture (2 minutes per scan position includes 360° scans and panoramic images) allows crews to digitally document large areas quickly and, repeatedly. This "change detection" capability expands the use cases for SOH's services.