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/ TOOLBOX
production of as-built plans of oil and gas
facilities. This seemed like something that
could be adapted to the surveying field and
be a real game changer. The Cyrax system
could scan a surface at a rate of 800 points
per second. It could “paint” a surface with
3D dots and build a cloud of points that
could provide accurate measurements and
used to draw 2D plans and produce detailed
3D models.
There are several types of lidar data capture
that exist and are worth considering when
planning out projects. The main methods
of capture are terrestrial, mobile and
aerial. Terrestrial lidar is a method using
an instrument usually set on a tripod, at
fixed locations around a site. There are
targets around the project site to help relate
one scan to another. Some of the more
accurate scanners use this method and are
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ideal when searching for the crispness that
might be needed for particular projects. High
performance scanners can create fine detail
scans of architectural features, such as molded
plaster medallions or ornate trim work inside
of a building. Others are geared more for
exterior work, such as topographic surveys.
Mobile and aerial lidar are very similar
methods where the scanner is mounted on a
mobile platform. They use inertial navigation
units and some ground control points to help
keep the errors related to the movement of the
vehicle to a minimum. These methods have
been used very successfully on route surveys
or large project areas. Some newer methods
involve the use of pedestrian-based scanners
that allow someone to walk through spaces. The
future possibilities of the UAV (unmanned aerial
vehicle or drone) market are on the horizon and
will take us to places that planes can’t.