McKim & Creed takes to the skies for surveying work
May 13, 2013By Andrew Gray
Inspecting miles and miles of power lines can be a daunting task for anyone to complete, but the engineers at McKim & Creed have found a way to use helicopter-mounted lasers to make traditional surveying faster by capturing detailed information and building a digital map.
The system, Laser Imaging Detection and Ranging (LiDAR), works similar to radar but uses laser light to record data.
The scanners record 200,000 data points per second using a laser scanner and combines the data with systems that track the motion of the scanner to create an accurate map of the area scanned.
Because the helicopter is moving, the scan data is useless without an Inertial Motion Unit (IMU), said Tim Cawood, senior vice president with McKim & Creed and head of its geomatics group.
“The IMU and a GPS corrects for vehicle motion,” said Cawood, who works in the Raleigh-based engineering, surveying and planning firm’s Wilmington office.
Once the data is collected from one of the two equipped helicopters the company uses, it is brought back to the McKim & Creed offices, where a team of 30 works with the data and merges it with other sources to create the final product.
“The data gets corrected and brought to real-ground coordinates,” Cawood said. “There are millions of points that no one can use. The final product is not the point cloud. It is a map derived from the point cloud.”
The firm purchased its first LiDAR system in 2001 shortly after static scanners first became available, company officials said.
After finding uses for the tripod-mounted scanner, the company purchased a truck-mounted system.
“After, we bought the mobile system [two sensors on a vehicle], the next logical is on an aircraft. Having knowledge of how it works, having the software and the technical staff, it was natural for us to get into airborne LiDAR,” Cawood said.
Helicopters of Hampstead owns the aircraft, and McKim & Creed owns the LiDAR equipment mounted on the helicopters.
McKim & Creed’s LiDAR airborne systems have a wide range of application including mapping roads, rail lines, forestry land and other cross-country infrastructure. But scanning power transmission lines is the majority of the firm’s business, Cawood said.
Transmission lines are the high voltage lines that form the backbone of the nation’s power grid.
Cawood said a new requirement was the reason the company invested in the airborne version. The North American Electric Reliability Corp. (NERC) issued a directive stating that owners of transmission lines had to confirm that their lines were a safe distance from vegetation and other conductors.
According to an article in Transmission & Distribution World magazine, utilities were told to verify 450,000 miles of lines within six months and all line by the end of 2013. As part of the announcement, NERC said that LiDAR was an acceptable method to determine if the lines were within specifications and detailed specific methodologies.
“That is what got us into it,” Cawood said. “We invested in two sensors and put them both on helicopters.”
For scanning power transmission line, “we have to collect 25 points per square meter or more, which means we have to fly low and slow – that is why we use a helicopter,” he said. “One of our sensors is now on an aircraft. It is for topographic mapping, and it collects two points per square meter.”
The system also captures images in both visible and infrared light in addition to laser scanning data.
Cawood said the helicopter has four cameras: one focused straight down, one for infrared imagery, one that faces forward and one that faces backward.
The images can be mapped onto the point data to produce more detailed maps. The capturing of the data creates a monumental amount of data.
“Our storage solution is scalable to 200 TB [terabytes],” Cawood said. “We average about 70 miles per day flying transmission lines.”
Greenfield Lake Amphitheater site update
Local web developer Peter Mills recently updated Greenfield Lake Amphitheater’s website.
Mills had built two previous version of the website (greenfieldlakeamphitheater.com) for the city-owned amphitheater and recently released a new version that includes an updated event calendar, integration with a photo sharing website and recordings of past concerts.
In addition to the new content, the site is also now “responsive” and automatically changes format depending on the size of the browser used to access the site.
Responsive design allows the website to work on a wide range of browsers from smartphones to tablets to desktop giant monitors, all with the same content.
Mills, owner of web development company Waveminded Studios, said the amphitheater’s website was “more like a hobby,” than something he is paid to do.
“I have partnered up with some of the promoters and [local radio station] The Penguin,” he said. “I reached out and asked, ‘What would help you [promote shows better at the amphitheater].’ ”
In addition to building the new version of the site, Mills also maintains its upcoming event list.
“Pretty much all the promoters will call me or send me an email. They also have a password to add events.” Mills also owns the Facebook page (facebook.com/greenfieldamphitheater) and Twitter account (@greenfieldamp) for the amphitheater.
“The Facebook page has over 3,400 fans, and I feel like we broke 2,000 at the end of last season.
I drive traffic to the website via the Facebook page. I really want to promote it as a central hub,” Mills said.
As part of the redesign, the website also incorporates photo-sharing site Instagram for people taking pictures at the shows.
“If you tag a photo with #GFLAMP, the photo will stream to the website almost immediately. It is basically using a call to Instagram to get the feed data for this tag,” he said.
Mills said the amphitheater’s website received more than 10,000 visitors last summer during the height of concert season.
“A lot of the traffic is from Raleigh. I think a lot of people who come from Raleigh or Myrtle Beach stay locally,” he said.
“It hits a peak mid-summer and tapers towards late September.”