TECHNICAL
This is invaluable when assessing the current physical
conditions of a city or town.
More recent advances in the technology have seen
systems become mobile and flexible, giving surveyors
and planners the ability to create an accurate digital
elevation model and maps in a matter of hours. The
processed data allows accurate positional data to be
accessed for manholes and other assets, as well as
allowing the creation of a 3-D visualisation of the inside
and outside of buildings.
Unlike sound and radio waves, light is obviously incapable
of passing through solid matter. LiDAR is therefore
unable to detect underground elements such as sewer
pipes. However, when combined with ground penetrating
radar, this technology can accurately map an entire city’s
infrastructure and reproduce all these elements in three
dimensions, all to an accuracy of under 1cm.
The millions of measurements collected by the system
are used to create a ‘point cloud’, or digital, three-
dimensional model of the area or object scanned. The
resulting data can be used to retrospectively analyse
the target to gain insights into positioning, dimensions,
and structural condition, as well as assist with planning
upgrades and changes by providing a millimetre-
perfect representation of the landscape. This also could
identify buildings, street furniture and other obstacles
that will need to be considered before construction
work begins.
LiDAR data is becoming increasingly vital in urban
planning because of its value in applications such
as business information modelling (BIM) and asset
www.plumbingafrica.co.za
management, in addition to the ability to track and
monitor changes in the landscape. South Africa relies
heavily on its 500-plus government-owned dams to
supply the nation’s water for drinking, crop irrigation,
and industrial processes such as mining. With over
10 billion cubic metres of water being used from the
country’s dams each year and levels having seen
dangerous lows in 2016, the government and its water
and sanitation minister are keeping a close eye on dam
levels countrywide.
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3-D visualisation showing
an example of a pipeline
placement.
Dams have long been monitored for structural
deformation using terrestrial laser scanners; yet,
changes in water levels can now also be assessed
quickly and accurately using airborne LiDAR systems.
When attached to a helicopter, plane or even a drone,
large areas can be mapped in a matter of minutes,
meaning repeat scans are more cost effective and
meaningful for monitoring purposes.
With much of the continent’s valuable water
infrastructure being at risk of failure, a huge amount can
be achieved by applying the latest technology to ensure
that growth is possible and supportable for our growing
cities and their communities for years to come. PA
Changes in water levels
can now also be
assessed quickly and
accurately using
airborne LiDAR systems.
May 2017 Volume 23 I Number 3