Shoreline detection technique
What is the accuracy of this shoreline?
Validation at Sand Motor, NL
Single satellite image (16-7-2015)
pixel resolution Sentinel (10 m)
Hoek van Holland
average 1 m
standard deviation 5 m
Hagenaars et al.
But can we also determine trends?
Show messy animatino
Image composition to overcome clouds, etc.
Composite images: moving time averaging
• Clouds, tidal stages, surge, waves, shadows, seasonal effects, etc.
Multi-year validation @ Sand Motor
2012 2013 2014 2015 2016
Can we analyze the coastline dynamics
of all beaches in the world?
Literature on beaches worldwide
Percentage sandy beaches; literature says: 10 – 70 %
Bird (1985): 70% of sandy beaches are eroding
1) Where are the world’s sandy beaches located?
2) How have these beaches changed over the last decades?
Storage and Compute
Landsat Satellite Data
NASA Landsat and Google Earth Engine
All free available
(Landsat) since 1987
For Hue, Vietnam
filtering of clouds,
• Machine learning with OSM Data (Texel, NL)
True Positive 99.9%
False Positive 1.8%
Training Dataset Sand Classification
Location of world’s sandy beaches
Construction of jetties caused accretion of
the northern beach of 9 m/yr, while the
southern beaches are eroding with 4 – 8
New York, USA
Hurricane Sandy caused
erosion of the dunes at Fire
Island. The eroded sand was
deposited at the foreshore
resulting the widest beach in 15
years, but the waves and wind
bring back the sand to the
dunes. This results in a
reduction of the beach width in
the years after the hurricane.
This is a nice example on how
resilient our beaches can be as
long as time allows to recover.
Beach erosion & accretion
per country in m/yr
1. Bahamas -2,10
2. Grenada -0,67
3. Cuba -0,64
4. Mexico -0,26
5. Honduras -0,23
1. Myanmar -1,90
2. Bangladesh -1,77
3. India -0,43
4. Pakistan -0,28
5. Yemen -0,28
1. Bahrein 4,79
2. Singapore 4,25
3. China 3,25
4. Kazakhstan 2,94
5. Turkmenistan 2,51