LiDAR B th t i SLiDAR Bathymetric Survey in Golfe du Lion ... · LiDAR Bathymetric Survey in Golfe...
Transcript of LiDAR B th t i SLiDAR Bathymetric Survey in Golfe du Lion ... · LiDAR Bathymetric Survey in Golfe...
1
LiDAR B th t i SLiDAR Bathymetric Survey in Golfe du Lion, France
www.fugro.com
Hugh Parker
Fugro LADS Corporation Pty Ltd
Hydro 2010
Rostock, Germany, 2-5 November 2010
LiDAR Bathymetric Survey in Golfe du Lion, France
Introduction Survey Objectives Survey Requirements Project Teamj Survey Area LADS Mk II ALB System Survey Control (Datums) Data Collection Plan
– Reconnaissance– Tides– GPS
Data Processing
www.fugro.comHydro 2010, Rostock, Germany, 2-5 November 2010
Data Processing Quality Control Conclusion
2
LiDAR Bathymetric Survey in Golfe du Lion, France
Survey Objectives
Survey was conducted for the Regional Directorate for Environment of Languedoc-Roussillon (DREAL), Littoral Zone Division to for Coastal Zone Management purposes
Objectives of the survey were:
– Map the sand reserves along the Languedoc-Roussillon coastline to assist decision making and strategy development by Local Government and coastal planners.
– use the data in the creation of a seamless regular digital altimetric model of the sea and on adjoining portion of land (as part of SHOM’s Litto 3d program
Data requirements
www.fugro.comHydro 2010, Rostock, Germany, 2-5 November 2010
Data requirements
– coastal topographic elevation data
• Coverage required from the vegetation line (back of the beach)
– coastal bathymetric elevation data
• Coverage to 10m isobath
Hydro 2010, Rostock, Germany, 2-5 November 2010
LiDAR Bathymetric Survey in Golfe du Lion, France
Survey Requirements Airborne LiDAR Bathymetric Survey of
Languedoc-Roussillon Coastline– Vertical accuracy
IHO d 1b• IHO order 1b– Resolution
• 5m average ungridded point spacing– Sounding coverage
• Gap minimisation by managing turbidity
• A minimum coverage requirement of 85% in all required areas
– Survey of Bathymetric Control Areas
www.fugro.comHydro 2010, Rostock, Germany, 2-5 November 2010
– Provide Aerial Imagery– Heights relative to the IGN69 Datum
Hydro 2010, Rostock, Germany, 2-5 November 2010
14 coastal areas awarded totalling ~313 sq.km
3
LiDAR Bathymetric Survey in Golfe du Lion, France
Project Team Members
Fugro LADS Corporation
– Collect data using LADS Mk II Airborne LiDAR Bathymetry (ALB) system along entire Coastal region
– Install and recover all temporary tide gauges
– Process all LADS Data
Eurosense
Pro ided contract administration s pport
www.fugro.comHydro 2010, Rostock, Germany, 2-5 November 2010
– Provided contract administration support
– Geodetic support
– Provision of additional French speaking pilot
LiDAR Bathymetric Survey in Golfe du Lion, France
Fugro LADS Mk II ALB System
Laser Airborne Depth Sounder (LADS)(LADS)
Hydrographic Survey / Coastal Mapping system mounted inside an aircraft
Pulses of laser light are used to measure the depth of water and height of features (ie rocks, islands, beach
www.fugro.comHydro 2010, Rostock, Germany, 2-5 November 2010
gradients)
4
LiDAR Bathymetric Survey in Golfe du Lion, France
LADS Mk II ALB Capabilities
1Khz System
Variable spot spacing: 2x2, 2.5x2.5, 3x3, 4x4,
5x5 or 6x6 metres5x5 or 6x6 metres
Swath width 50 - 300 metres
Variable altitude 1200 – 2200 feet
Tidal and / or Ellipsoidal datum
Maximum depth capability to 70m (subject to
suitable water clarity)
Topographic height range 0 to 50m
www.fugro.comHydro 2010, Rostock, Germany, 2-5 November 2010
p g p g g
Aerial Photography (0.25m Resolution)
Relative Reflectance
IHO Order 1 position, depth accuracy and
target detection (subject to water clarity)
Hyperspectral scanner
LiDAR Bathymetric Survey in Golfe du Lion, France
Survey Control and Datums
Horizontal Control
– Real Time Horizontal control
GS O S G S• WGS 84, OmniStar Wide Area DGPS
– Post Processed Horizontal control
• ETRF89 Ellipsoid, Post Processed KGPS positions using Temporary GPS Base Stations at Montpellier and Port-la-Nouvelle.
Vertical Control
– IGN69 Vertical Datum, through tidal reduction using Permanent Gauges (via SHOM) at Port
www.fugro.comHydro 2010, Rostock, Germany, 2-5 November 2010
using Permanent Gauges (via SHOM) at Port Vendres, Sete and Marseilles, and temporary gauges installed at Post-la-Nouvelle and Port Camargue
5
LiDAR Bathymetric Survey in Golfe du Lion, France
Reconnaissance
Conducted over 1 week between 20 – 28 July 2009, and included:
– Kick off meetings with Customer and SHOMSHOM
– Meetings with airport authorities to discuss low level flying operations
– Locate suitable locations for GPS Base Station and Temporary tide gauges
– Conduct water clarity measurements to evaluate nature of water clarity in the area in different weather conditions
– Coastline study to understand nature of
www.fugro.comHydro 2010, Rostock, Germany, 2-5 November 2010
coastline
– Liaise with locals regarding weather and nature of
LiDAR Bathymetric Survey in Golfe du Lion, France
Outcomes of Reconnaissance:
The water clarity in the survey area is highly dependant upon the weather conditions:
St th t i d t h d b ki– Strong south east winds generate heavy seas and breaking waves along the coastline stirring up the inshore water and degrading the water clarity.
– Strong north west winds push water from the adjacent coastal lakes into the sea; this also degrades the water clarity along the coastline, especially around the inlets/marinas.
Even after 48 hours of good weather, water with degraded clarity was still evident around marinas and inlets.
www.fugro.comHydro 2010, Rostock, Germany, 2-5 November 2010
Early morning flights are advised for the following reasons:
– Calmer sea conditions
– Less boat activity on the water
– Beaches are less populated
6
LiDAR Bathymetric Survey in Golfe du Lion, France
Tidal Reduction
Temporary tide gauges installed at Port-la-Nouvelle and Port Camargue were
Sete (SHOM)
Port Camargue (FLC)
and Port Camargue were connected to datum (IGN69) via levelling from local IGN benchmarks at each area
Pole/Gauge comparisons were conduced at each location to ensure gauges were calibrated and operating correctly.
Port-la-Nouvelle (FLC)
( )
Marseille (SHOM)
www.fugro.comHydro 2010, Rostock, Germany, 2-5 November 2010
Port Vendres (SHOM)
LiDAR Bathymetric Survey in Golfe du Lion, France
Horizontal Positioning
2 Temporary base stations established at Port-la-Nouvelle and at Montpellier on the roof topand at Montpellier on the roof top of prominent buildings (i.e. hotel rooftop)
Ensured maximum baseline lengths <55 kms for the entire survey area
positioned via network solution using surrounding stations from the National IGN CORS network
<55 kms
Montpellier
www.fugro.comHydro 2010, Rostock, Germany, 2-5 November 2010
the National IGN CORS network
<55 kms
Port-la-Nouvelle
7
LiDAR Bathymetric Survey in Golfe du Lion, France
Fugro LADS Line Planning
Line planning prepared that divided the area up as to survey the areas as
15
efficiently as possible
www.fugro.comHydro 2010, Rostock, Germany, 2-5 November 2010
LiDAR Bathymetric Survey in Golfe du Lion, France
Bathymetric Control Areas
SHOM determined location of Three Bathymetric Control Areas
Saintes Maries de la MerAreas– Canet-Plage– Cap d’Agde– Saintes Maries de la Mer
Located in depths of water between 2-6m of water
Cap d’Agde
www.fugro.comHydro 2010, Rostock, Germany, 2-5 November 2010
Fugro LADS flew over one of these control areas at the beginning and end of each sortie to confirm system accuracy.
Canet-Plage
8
LiDAR Bathymetric Survey in Golfe du Lion, France
Bathymetric Control Areas
www.fugro.comHydro 2010, Rostock, Germany, 2-5 November 2010
Canet-Plage
LiDAR Bathymetric Survey in Golfe du Lion, France
Fugro LADS LiDAR Data Collection
Aircraft arrived in Montpellier on Friday 21 August 2009
Data collection commenced 24 AugustData collection commenced 24 August
9 flights flown of which all were fully effective
Average 4:49 on task (collecting data) per flight
Average 1:00 transit/Benchmarks per flight
Total 43:23 hours of on task time achieved
Over 280 lines flown, over 470 sq.km of data collected
Aircraft departed Montpellier 09 September 2009
www.fugro.comHydro 2010, Rostock, Germany, 2-5 November 2010
p p p
9
LiDAR Bathymetric Survey in Golfe du Lion, France
Data Processing
Automated Initial Processing and depth selection
I iti l Fi ld Ch k C d t d (i Initial Field Check Conducted (in Adelaide for this project)
Field cleaned pre-validated data set produced with 24 hours of last flight
Comprehensive validation and checking process conducted in Adelaide office
Data quality checked on completion of
www.fugro.comHydro 2010, Rostock, Germany, 2-5 November 2010
process
Data then approved for use in products by Senior IHO Cat A Surveyor
LiDAR Bathymetric Survey in Golfe du Lion, France
Field Processed Data
Automatic data processing and initial Pre-Validation was conducted in the field directly after each flight to confirm system performance after each sortie
High quality “Pre-Validated” interim LADS data available on completion of data collection
Coverage plots generated and refly lines identified where
www.fugro.comHydro 2010, Rostock, Germany, 2-5 November 2010
needed
Data then released for detailed and comprehensive validation and review in accordance with Fugro LADS quality processes
10
LiDAR Bathymetric Survey in Golfe du Lion, France
Control by SHOM:• Coverage• Density• Data check by a SHOM’s operator:
all the data are checked (720 cases of control)• Crosscheck for crossline and line by line• Comparison with SHOM’s database• In Situ control• Comparison with SHOM’s control areas (3 areas)• Comparison with non SHOM surveys• Conform for the 46 requirements (technical specifications from SHOM)
For QC Fugro LADS Provided to SHOM:
www.fugro.comHydro 2010, Rostock, Germany, 2-5 November 2010
For QC, Fugro LADS Provided to SHOM:• Approved data in LADS proprietary CAF format which included the raw
laser waveforms• This format is compatible with both CARIS and Fledermaus
software. SHOM used both packages during the QC process• Individual digital images from the Downward looking camera in the
LADS Mk II ALB system.
LiDAR Bathymetric Survey in Golfe du Lion, France
Case of control example by SHOM’s operator
Same Feature
www.fugro.comHydro 2010, Rostock, Germany, 2-5 November 2010
11
LiDAR Bathymetric Survey in Golfe du Lion, France
Comparison with SHOM’s control areas (3 areas)
www.fugro.comHydro 2010, Rostock, Germany, 2-5 November 2010
Cap d’AgdeOne of the 3 Shom’s control area
Mean Depth Difference 5 cm
Standard Deviation 9 cm (95%)
LiDAR Bathymetric Survey in Golfe du Lion, France
Coverage Achieved
Results were achieved with depths down to the required 10 m obtained and in most areas depths beyond 20 metres were achieved
Coverage of >95% achieved in all areas
IHO order 1 accuracy achieved
Mean Depth Difference between the cross lines and
1 Persistent turbidity around Cap l'Espiguette. Operations within these areas were attempted throughout the survey, however conditions in
2 A small gap exists at the mouth of the Petit Rhone River in the eastern extent of the area deeper than 7-8 metres
www.fugro.comHydro 2010, Rostock, Germany, 2-5 November 2010
main lines was 0.01 ±0.08 metres (1)
Some localized gaps in the coverage occurred as indicated
survey, however conditions in these areas remained marginal and depths to only 6-7 metres were achevied in this area.
area deeper than 7-8 metres where persistent turbidity was evident.
12
LiDAR Bathymetric Survey in Golfe du Lion, France
www.fugro.comHydro 2010, Rostock, Germany, 2-5 November 2010
LiDAR Bathymetric Survey in Golfe du Lion, France
Conclusions A successful LiDAR Bathymetry survey was of >310 sq.kms was conducted in
9 flights over
Data quality exceeded customer expectations in terms of coverage and i lvertical accuracy agreement
A seamless topographic / bathymetric data set has been produced
www.fugro.comHydro 2010, Rostock, Germany, 2-5 November 2010
13
LiDAR Bathymetric Survey in Golfe du Lion, France
Acknowledgements
Additional Author’s
– Mr Mark Sinclair, Managing Director, Fugro LADS Corporation Pty Ltd
– Mr Yves Pastol, Hydrographic Surveyor, Service Hydrographique et Oceanographique de la Marine (SHOM)
Mr C ril Vanro e Unit Manager Sedimentar
www.fugro.comHydro 2010, Rostock, Germany, 2-5 November 2010
– Mr Cyril Vanroye, Unit Manager Sedimentary Dynamics and Coastal Hazards, Regional Directorate for Environment of Languedoc-Roussillon (DREAL)
LiDAR Bathymetric Survey in Golfe du Lion, France
Thank You
www.fugro.comHydro 2010, Rostock, Germany, 2-5 November 2010