Page 37 - NSAA_Fall2015Journal

groomed. Another grooming manufacturer, PistenBully, has
its own slope management system called SNOWsat, which
uses differential GPS in conjunction with 3D mapping for
snow depth measurement.
“Combining LIDAR and snow-depth sensor technol-
ogy can help resorts measure undulations down to the inch,”
Panarisi said. “We’re not completely there yet at Stratton,
but we’re getting really close. There’s no software that over-
laps snow sensors and LIDAR, so we’re kind of extrapolating
on our own.” Using the technologies, Panarisi runs reports of
every grooming pass, along with color-coded readouts of the
snowpack. “Every pass you make, you get a strip. Depending
on the width of the run, you can get anywhere from 20 to
100 strips to study,” he added.
That real-time information lets him quickly identify high traf-
fic areas that may benefit from additional snowmaking or groom-
ing, and is especially effective when planning the resources and
manpower he needs to allot each season to build his terrain park.
“As long as you’re not moving your terrain park to a new
trail every year, you can use 3D mapping and GPS to dial in
all the coordinates for how many acre feet of snow you need,
how long you need to blow snow, and how many man-hours
it’s going to take to push all those [snowmaking] whales out,”
said Panarisi. “Nothing’s worse than moving the guns, push-
ing out the snow, and finding out you didn’t make enough…
so most resorts overdo it, and that’s the expensive part.”
As for the upfront costs and in-house expertise to use
LIDAR, the information is free for Stratton and other areas
in Vermont to access. Vermont’s LIDAR Initiative was cre-
ated to “democratize” and share the availability of the state’s
topographical mapping data. And high-resolution LIDAR
mapping can also be publicly accessed in many other states,
courtesy of the US Geological Survey and your tax dollars.
But in terms of whether other Vermont or US ski areas are
taking advantage of 3D mapping to cut their snowmaking and
grooming expenses, Panarisi said, “I’m hearing more discussions
about it, but I couldn’t tell you who else is making the commit-
ment. I think there’s always going to be a sense of proprietary
knowledge to some of this stuff, and you definitely need your
senior team’s support to purchase something like the snow sen-
sors, which in our experience quickly paid for themselves.”
The snow sensors cost Stratton $25,000 to $30,000
per machine, and the resort also took advantage of incen-
tives offered by the electric utility through the state-wide
Efficiency Vermont energy-savings initiative. “Other states
have similar programs, and it’s well worth finding out if
they’ll help pay for these upgrades,” Panarisi said. (Read
more about the program in the article “The Great Snow
Gun Roundup: Efficiency Vermont Sparks Statewide
Megawatt Savings,” Convention Issue 2015.)
THE EVOLUTION OF 3D MAPPING
As mentioned, in addition to the cost-savings related to 3D
mapping at ski areas, the technology has another compelling
benefit: providing an exact sense of how the resort looks
and feels without actually being there in person. In 2013,
when Google announced it had made 3D maps of 38 US ski
areas available on Google Maps (http://3dskimaps.com), one
WHAT IS LIDAR?
LIDAR, which stands for Light Detection and Ranging, is
a remote sensing method that uses light in the form of
a pulsed laser to measure ranges (variable distances) to
the Earth. These light pulses—combined with other data
recorded by the airborne system—generate precise,
three-dimensional information about the shape of the
Earth and its surface characteristics.
A LIDAR instrument principally consists of a laser, a
scanner, and a specialized GPS receiver. Airplanes
and helicopters are the most commonly used
platforms for acquiring LIDAR data over broad areas.
Two types of LIDAR are topographic and bathymetric.
Topographic LIDAR typically uses a near-infrared
laser to map the land, while bathymetric uses water-
penetrating green light to also measure seafloor and
riverbed elevations.
LIDAR systems allow scientists and mapping
professionals to examine both natural and manmade
environments with accuracy, precision, and flexibility.
NOAA (National Oceanic and Atmospheric
Administration) scientists are using LIDAR to produce
more accurate shoreline maps, make digital elevation
models for use in geographic information systems,
assist in emergency response operations, and in many
other applications.
HOW IS LIDAR DATA COLLECTED?
When an airborne laser is pointed at a targeted area on
the ground, the beam of light is reflected by the surface
it encounters. A sensor records this reflected light to
measure a range. When laser ranges are combined with
position and orientation data generated from integrated
GPS and Inertial Measurement Unit systems, scan angles,
and calibration data, the result is a dense, detail-rich group
of elevation points, called a “point cloud.”
Each point in the point cloud has three-dimensional spatial
coordinates (latitude, longitude, and height) that correspond
to a particular point on the Earth’s surface from which a laser
pulse was reflected. The point clouds are used to generate
other geospatial products, such as digital elevation models,
canopy models, building models, and contours.
Courtesy of the National Oceanic and Atmospheric
Administration, http://oceanservice.noaa.gov/facts/
lidar.html, August 4, 2015.
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