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9
July - September 2014
Innovative mapping solutions for the Pacific
Unmanned aerial vehicles (UAVs) were the stuff
of sci-fi geeks and conspiracy theorists. Now that
technology has reached the Pacific and is being used
in disaster assessments and coastal mapping.
In April this year a rotary-wing UAV, an “Oktocopter”,
was used to assist damage assessment efforts in the
Solomon Islands. The exercise proved that UAVs were
a useful technology for rapid mapping in a disaster
response situation. The digital surface models
produced from that mission also provided the first
aerial views of where the tailings dam of a large mine
had been compromised thus a potential problem for
communities downstream of the site.
In July 2014, a fixed wing UAV, TRIMBLE UX5, was
purchased by the SPC to assist coastal mapping
initiatives across the Pacific region. The UAV is part
of a larger package; an Unmanned Aerial System
which includes the hardware, software and requisite
training to operate the UAV and analyse the data
collected. A test run in Kiribati proved that not only
is it possible to acquire very high resolution imagery
in a relatively short period of time, it is also possible
to capture elevation data. The long lasting battery
life (50 minutes) combined with the UAV cruising
speed of 80 km/hour allows large areas to be mapped
efficiently. Additionally, the quality of the mounted
camera (SONY) brings the resolution of the output
(orthophoto and point cloud) to a range between less
than 3 cm to 24 cm depending on the programmed
height of the UAV.
SPC has a small team of experts who are being
trained to control the UAV and also analyse the data
produced. Initial analysis of the data provided high
resolution imagery and digital surface models of the
area. Through the past month, the team has been
analysing the data and processing this against good
surveying observations to produce digital terrain
models. Comparisons with Real-Time Kinematic GPS
survey points show that the results are comparable
and therefore a possible source of elevation data
for areas where ground topography is limited. This
dataset is particularly important for inundation
studies.
It is anticipated that as the team uses the UAV under
different conditions and analyses the data captured,
other potential applications will become apparent.
The images show 24 cm resolution point cloud which is the lowest quality the UAV can produce. The resolution can be
increased by a factor of 10 with adequate permit from Civil Aviation Authority