AERIAL SURVEY OF FIX ASSETS IN THE RIGHT-OF WAY
Huug HAASNOOT, the Netherlands
Key words: LiDAR, Corridor Mapping, 3D-geometry,
Ortho-rectified, geo-referenced video images, Automatic Filtering
Routines, Synchronised video imagery.
Abstract
High density airborne LiDAR, being an innovation in remote sensing
techniques, have now taken away the barriers of the traditional survey
techniques. Especially for long corridors like roads, railway and
electricity lines, laser alitimetry provides a new survey method to
collect remotely sensed data in a quick way. In this lecture emphasis
will be put on LiDAR systems which operate with the latest technology
at low altitude (50-70 m) and low speed (50 km/hour) which results in
a survey tool that can compete with traditional survey methods as it
is precise (5-8cm absolute accuracy), reliable, fast (150 km per day)
and cost-effective.
The advantages of aerial surveys are twofold: obviously the safety
aspect is very important as surveyors are not required to physically
occupy the area and secondly for the train / road operators it is
essential that the survey will not interrupt the schedule of the
transport. Further aerial surveys are not compromising the
environmental conditions, nor any permits are required to have access
to every property.
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The integration of numerous latest innovations such as the high
frequency scanning laser, the solid state Inertial Navigation System,
kinematic GPS technology, automatic filter routines and mosaic of
digital ortho-rectified video images has provided numerous industries
a new survey tool and a near continuous 3D-geometry coverage of
terrain features. This, in combination with dedicated software, has
resulted in an outstanding tool to inventorise corridors for the
railway, pipeline, electricity, and tele-communication industry. The
technical side of this new innovative survey solution will be
discussed and explained in detail.
The high density (10-20 points per m2), high accuracy data enables
the surveyor to map all assets along corridor like railway tracks and
powerlines to a details of signals, tracks, junction boxes, sag of
conductor lines, the location and height of existing buildings, etc.
This information can also play an important role in the determination
of the optimum route for a new line.
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A dedicated processing package supplies filter algorithms and CAD
functionality "on top of" the laser data as well as fully
synchronised video imagery, providing additional capabilities to the
operator in extracting valuable information from the LiDAR data. This
extracted information can easily be incorporated in external specific
GIS or CAD software packages.
As long corridors do not lend themselves well to conventional land
survey techniques, this new high-detail aerial survey method has been
used successfully world-wide with a total of more than 13,000 survey
kilometres.
During the last 1.5 years projects have been completed in various
industries with a variety of endproducts, e.g. detailed Digital
Terrain Models with more than 10 points per m2 for flood control,
planning of new roads for the expansion of tourism on French
Polynesia, high-accuracy cross-profiles of the Expressway near Kuala
Lumpur, planning of noise protection walls for the German railroad,
coast line protection survey in Portugal.
In more detail a major project executed for Spoornet, the South
African railway division of Transnet, will be discussed during this
presentation session. This project comprised of surveying 3 875 km of
heavy haul railway lines covering all fixed assets in the
right-of-way. The purpose was to define the accurate geographic
position and attributes of all fixed assets in order to build an
integrated information system to manage and maintain the fixed railway
assets. Given the inaccuracies and incompleteness of the historic
asset records, the decision was made to re-survey Spoornet's
mainlines. As conventional landsurvey methods were more expensive and
time consuming, the project was executed with FLI-MAP, the laser
altimetry system from Fugro, in close liaison with the Chair of
Railway Engineering at the University of Pretoria (South Africa),
Prof. Ebersöhn.
BIOGRAPHICAL NOTE
Huug Haasnoot has more than 12 years experience in the
survey industry after graduating in 1988 from the Technical University
of Delft, The Netherlands, with a MSc. in Geodesy.
He is currently working for Fugro-Inpark B.V. in the Netherlands
and as Director of the division FLI-MAP® responsible for all corridor
mapping projects with the laser altimetry system FLI-MAP® in the
Eastern Hemisphere.
Fugro-Inpark B.V. is an engineering and consultancy company,
offering expertise and project support in the areas of geographic
information systems, and their applications to photogrammetry,
subterranean infrastructure, telecommunications, railroad industry,
electricity utility industry and civil engineering.
CONTACT
Huug Haasnoot
Director
Fugro-Inpark B.V.
Division FLI-MAP
P.O. Box 3000
2260 DA Leidschendam
THE NETHERLANDS
Tel. + 31 70 31 70 700
Fax + 31 70 31 70 750
Email: h.haasnoot@fugro-inpark.nl
23 March 2001
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FIG Office. Last revised on 05-11-25.
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