Presentation by Gerben Hagenaars and Arjen Luijendijk (Deltares) at the Symposium Earth Observation and Data Science, during Delft Software Days - Edition 2017. Friday, 3 November 2017, Delft.

1. Global Sandy Shoreline Dynamics
derived from Satellite Imagery
Arjen Luijendijk,
Gerben Hagenaars & Josh Friedman,
Gennadii Donchyts & Fedor Baart,
Stefan Aarninkhof,
Rosh Ranasinghe
Delft Software Days
03 November 2017

2. Understand the system
Is this beach
eroding?
Has anybody been
looking at this
beach for the last
30 years?
YES!

3. 3

4. 4

6. Automated shoreline detection
shorelinewater
land
NDWI
no.ofpixels
landwater
What is the accuracy of this shoreline?
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7. Validation
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8. Sand Motor, NL
Single satellite image (16-7-2015)
pixel resolution (10 m)
offset[m]
Scheveningen
Hoek van Holland
average 1 m
standard deviation 5 m
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9. Application
• Sand Motor case study
– 1-1-2011 // 1-7-2016
2012 2013 2014 2015 2016
distancealongtransect[m]
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10. Limitations
• Method works well at sandy shores
• Less quality at less sharp land-water transition
• Mud
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11. Sand classification
[Manual]
“Buildings”
[Automatic]
OSM Sand
Training Dataset Sand Classification
(Sentinel 2)
Classified
Sand
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12. Global Sand
Method shows good quantitative results
 Lets go global!
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13. 1. Sand classification worldwide
Hayes (1967)
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14. 32 % of the world coastline is sandy
of which 24% is eroding > 0.5 m/yr
while 28% is accreting > 0.5 m/yr
2. Sandy shore dynamics
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15. 2. Sandy shore dynamics
Ocean Beach, San Francisco: -4 m/yr
Tweed river bypass system:
+ 3.7 m/yr
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16. Demo time
(link)
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19. Suggestions / questions?

20. Average change rate of sandy shores
per country
Luijendijk et al. (in prep)

21. Luijendijk et al. (in prep)
North America:
1. Bahamas -2,10
2. Grenada -0,67
3. Cuba -0,64
4. Mexico -0,26
5. Honduras -0,23
Europe:
1. Romania -0,51
2. France -0,44
3. Portugal -0,44
4. Ukraine -0,37
5. Greece -0,09
Asia:
1. Myanmar -1,90
2. Bangladesh -1,77
3. India -0,43
4. Pakistan -0,28
5. Yemen -0,28
Asia:
1. Bahrein 4,79
2. Singapore 4,25
3. China 3,25
4. Kazakhstan 2,94
5. Turkmenistan
Average change rate of sandy shores
per country

22. 15
t
Composite images: moving time averaging
2. Shoreline detection

23. Accuracy
Tide + Surge Wave set-up Wave run-up

24. Shoreline change rates 1989-
2002 over 65 km coastline
Based on aerial photographs
every ~2 years
Blue line represents linear
regression based on obs data.
Hatteras Island, USA
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25. RMSE
Survey – SDW moving av.: 2.2 m/y
Survey – SDW single: 3.6 m/y
Distribution of errors
SDW moving av. - Survey
Hatteras Island, USA
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26. B: Hatteras Island
RMSE
Survey – SDW moving av.: 2.2 m/y
Survey – SDW single: 3.6 m/y
Distribution of errors
SDW moving av. - Survey
Method shows good quantitative results to map
shoreline dynamics
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