Bathymetric LiDAR – Lessons learned
Andrew Flatman
Rune Carbuhn Andersen
Data Acquisition
Danish Geodata Agency
Danish Geodata Agency - GST
• Our earliest experiences with Bathymetrisk LiDAR – 21. Dec. 2007
•
Opportunity for Bathymetric test 2009-2012
Why ”Bringing Land and Sea Together”?
Reasons:
•North Sea nations handle
geospatial data independently
• Little integration of land and
sea data
• Lack of collaboration between
countries
• Increasing pressure on coastal
areas
• Threat of climate change and
accelerated sea level rise
Goals:
•
Develop a product specification for
maritime and terrestrial features
•
Develop a new vertical datum for
the North Sea Region
•
Extensive testing of new airborne
laser techniques in the coastal zone
•
Deploy, update and test
metadatabase
WP3: Developing the Marine and Coastal Reference Base
WP4: Harmonisation of Maritime Information
WP6: Climate Change and Integrated Coastal Zone Management (ICZM)
The GST interest in Bathymetric LiDAR
Supplementary Survey techniques…
2. Classification by waveform…
1. Closing the gap…
3. Lakes and streams…
Test areas
3 different environments:
• Rødby
• Flensborg Fjord I & II
• Hirtshals
Challenges
Maturity – Operators / Systems
Local Environment – water and weather
Rødby
Hirtshals
Flensborg
April 2011 – Algae April 2011 – Algae July 2012 – Success
bloom
bloom
(Hawkeye II)
June 2011 –
June 2011 –
April 2013 –
Technical issue
Technical issue
Success
(Chiroptera)
February 2012 – February 2012 –
Low clouds
Low clouds
April 2012 –
April 2012 –
Success
Strong winds and
(Hawkeye II)
waves
July 2012 – High
turbidity
August 2012 –
Partly Success
(Chiroptera)
http://marcoast.dmi.dk/
Primary Goal – Closing the Gap (Flensborg Fjord)
Lots of rock
Hawkeye – deep scan
Chiropetera – high density
Deep scan (3 sechi) vs High density (1 sechi)
Accuracy – control points:
Usual check of topograhic LiDAR but Bathymetric LiDAR?
Accuracy: control points and object detection
Multibeam
Deep scan (3Depth:
sechi) 5 meter
Deep Scan - Hawkeye
High Density - Chiroptera
Distribution
Flying height: 400 meter
5 meter
Distribution in Flensburg Data:
Back to simple point cloud:
Density and penetration
LiDAR havoverflade
LiDAR bund
Points per m2
0.20 ppm2
0.21 ppm2
0.22 ppm2
0.23 ppm2
0.19 ppm2
0.007 ppm2
Depth
6.0 m
7.5 m
8.5 m
9.0 m
12.0 m
13.0 m
Multibeam bund
LiDAR bund
Preliminary Conclusion and Lessons learned ….
so far
•
Accuracy – Horizontal OK, Vertical assumenly OK
•
Density vs Object Recognition - ??
•
Logistic – local environment – a constant challenge in
Danish waters
•
Sofware and data processing tools for full waveform challange
Great Model - plenty of use in Coastal Zone Management
But for charts ????
The Road Ahead….
• Data analyze of Flensburg Fjord and Rødby - general QC
• Object recognition
• Cooperation with other organizations (BSH, …)
• Evaluation of Bathymetric LiDAR for Danish Waters
• Operational test in Greenland – 2015
• LiDAR Bathymetry for classification…
• LiDAR Bathymetry for lakes and streams…
• ……..