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GEOS2115/2915 Geocoastal Research Group
Coastal Datasets Practical – Week 6 School of Geosciences, The University of Sydney
Dr Ana da Silva and Dr Tommy Fellowes
2024 1 of 13
GEOS2115 / GEOS2915
Coastal Datasets Practical – Week 6
Today we will look at two open-access shoreline datasets. We will explore each dataset and
you will learn how to extract shoreline data from each at Narrabeen Beach. This practical is
a demonstration that gives you a working example of how to get the data, and in your own
time, you will follow the same steps to complete Narrabeen and your selected second beach
(Bondi, Maroubra or Curl Curl) for your Individual Report. That report is due in Week 9
(Friday 26th April at 11:59pm). See Canvas for more information.
NB: Today we will be using a Python Sandbox. Do not panic if you do not have coding
experience, as we will be running codes that are already written.
Part A: DEA Coastlines (estimated time: 30 to 45 minutes)
Digital Earth Australia Coastlines (https://www.dea.ga.gov.au/products/dea-coastlines)
Background
Australia has a highly dynamic coastline of over 30,000 km, with over 85% of its population
living within 50 km of the coast. This coastline is subject to a wide range of pressures,
including extreme weather and climate, sea level rise and human development.
Understanding how the coastline responds to these pressures is crucial to managing this
region, from social, environmental and economic perspectives.
The United States Geological Survey's (USGS) Landsat satellite program has been
capturing images of the Australian continent for more than 30 years. Digital Earth Australia
(DEA) Coastlines is a continental dataset that includes annual shorelines and rates of
coastal change along the entire Australian coastline from 1988 to now.
GEOS2115/2915 Geocoastal Research Group
Coastal Datasets Practical – Week 6 School of Geosciences, The University of Sydney
Dr Ana da Silva and Dr Tommy Fellowes
2024 2 of 13
The DEA Coastlines methodology is detailed in Bishop-Taylor et al. (2021) (Link to paper).
At a high level, they collect all the Landsat satellite images taken close to the median tide
level from a specific year for every location around Australia. Then, they remove the bad
pixels that have clouds and other interference such as sun glare. From this, they generate
an annual median composite image, i.e., a single usable mean image from the filtered
images. Afterward, they use a complex algorithm described in the paper above to create an
annual shoreline. The overall trends and retreat/grown rates are then calculated (see below).
The applications of the unique dataset include:
• Monitoring and mapping rates of coastal erosion along the Australian coastline.
• Prioritise and evaluate the impacts of local and regional coastal management based
on historical coastline change.
• Modelling how coastlines respond to drivers of change, including extreme weather
events, sea level rise or human development.
• Supporting geomorphological studies of how and why coastlines have changed
across time.
Today (and in your Individual Report) you will focus on two DEA Coastlines Products:
• Annual shorelines represent the median or ‘most representative’ position of the
shoreline at approx. 0 m Mean Sea Level for each year since 1988 (Figure below).
• Rates of change points dataset providing robust rates of coastal change for every
30 m along Australia’s non-rocky coastlines (Figure below). The most recent annual
shoreline is used as a baseline for measuring rates of change.
• The below figure shows areas of shoreline retreat in red and areas of shoreline
growth in blue. Areas with no overall change are white.
GEOS2115/2915 Geocoastal Research Group
Coastal Datasets Practical – Week 6 School of Geosciences, The University of Sydney
Dr Ana da Silva and Dr Tommy Fellowes
2024 3 of 13
Get the data: DEA Sandbox
1. Head to https://maps.dea.ga.gov.au/#share=s-DEACoastlines&playStory=1
and click through the tour at the bottom of the screen.
2. Click the ‘Explore map data’ button and add the DEA Coastline Layer. This is found
in the ‘Sea, Ocean and Coast’ tab. Select ‘DEA Coastline’. Click done in the top
right corner of the data window.
3. In the top lefthand corner use the search bar to find Narrabeen.
4. Zoom in on the beach and you will see annual shorelines from 1988 to now.
5. Now we will extract the data from Narrabeen Beach using the same locations of the
actual beach survey transects that have been collected monthly since 1976. NB: we
will be analysing these beach profiles in the Week 7’s practical.
6. Head to https://knowledge.dea.ga.gov.au/guides/setup/Sandbox/sandbox/ to quickly
read about the DEA Sandbox portal.
7. Now head to https://app.sandbox.dea.ga.gov.au/ and create an account using your
university email address. If you already have an account, just sign in.
8. Once logged in, you will be asked to click “Start” on the blue bar at the bottom of the
page. This will build your virtual environment. This may take a few moments.
9. The panel on the lefthand side of the screen is your directory containing many
documents and scripts you can analyse the DEA data. The panel on the right is
where the Python script will be displayed (see Figure Below).
10. Double-click on the folder “Interactive_apps” listed in your lefthand directory (Figure
above).
GEOS2115/2915 Geocoastal Research Group
Coastal Datasets Practical – Week 6 School of Geosciences, The University of Sydney
Dr Ana da Silva and Dr Tommy Fellowes
2024 4 of 13
11. Then double-click to open the “Coastal_transects.ipynb” code. See Figure below for
the first part of the code).
12. At the top of the code DEA Sandbox window click the “Run” menu and select ‘Run
all Cells’ (see below).
13. This will run each section (box) in the code. An example code box (section) is
shown below. The presence of a number between the “[ ]” (in this example a 1 is
shown) means the code has been successfully run.
14. Now scroll down until you see this section of code with the map of Australia and the
DEA coastline data (Figure below). This is how we extract the data along Transects.
On the left you see the transect options and on the right is the map.
GEOS2115/2915 Geocoastal Research Group
Coastal Datasets Practical – Week 6 School of Geosciences, The University of Sydney
Dr Ana da Silva and Dr Tommy Fellowes
2024 5 of 13
Troubleshooting: If you encounter any problems with the code e.g., if it is not loading
correctly or you load the incorrect transect shapefile (.geojson), you can clear all the output
and re-run the code. To do this click the “Edit” menu at the top left of DEA Sandbox screen
and select “Clear all output”. Once cleared you can re-run the code by repeating Step 13.
15. Now to help you, we have provided you with the shapefile for the Narrabeen Beach
Transects in the file “Narrabeen_transects_V2.geojson”. This file can be found on
the Canvas page for this practical. Download the file to your computer and make
sure you save it in a place you can find it later.
Download Narrabeen Shoreline Data
16. Now we will extract the shoreline data for Narrabeen at the same location of the field
beach surveys profiles (transects) collected since 1976.
17. In the section of code shown below, input the Output Name as “Narrabeen_output”.
Then make sure you have “Distance” selected in the drop down menu. Then click
the Output File for both “Figure (.png)” and “Distance table (.csv)”. In the ‘Advanced’
section click the “Upload” button and select the “Narrabeen_transects_V2.geojson”
you just downloaded from Canvas in Step 15.
Once loaded you will see the map on the right is now zoomed in on Narrabeen. You
will also see 3 black transect lines along the length of Narrabeen (see below). These
are our transect (PF1, PF4 and PF8) numbers from north. If the transect file has
loaded correctly you will see this line of text below the map “Uploaded
'Narrabeen_Transects_V2.geojson'; no 'id' column detected, labelling transects from
0 to 2.” See troubleshooting above to fix this.
GEOS2115/2915 Geocoastal Research Group
Coastal Datasets Practical – Week 6 School of Geosciences, The University of Sydney
Dr Ana da Silva and Dr Tommy Fellowes
2024 6 of 13
NB: In the DEA Sandbox code, you will have black transect lines that are bit hard to see on
the map in the above screenshot. We have manually added red transect lines to highlight
their locations for you.
18. Now Click the big teal coloured button “Extract shoreline data”. If successful you will
see the following code:
19. This code you will see the output timeseries from the 3 transects (see below). NB: in
this figure 0 = PF1, 1 = PF4 and 2 = PF8. These are numbered from the north end
of Narrabeen (see red lines in above figure for reference). In Excel changed the
names of the transects from 0, 1, 2 to the corresponding transect names.
PF1
PF4
PF8
GEOS2115/2915 Geocoastal Research Group
Coastal Datasets Practical – Week 6 School of Geosciences, The University of Sydney
Dr Ana da Silva and Dr Tommy Fellowes
2024 7 of 13
20. To get the timeseries data, double-click on the “deacoastlines_output” folder in the
directory panel on the left. This folder will contain 2 Narrabeen files:
“Narrabeen_output.png” and “Narrabeen_output.csv”. An example of the data in the
.csv file is shown below. Each Transect will have one value for each year between
1988 and now. These values are the distance between the landward end of the
transect lines and the shoreline for the corresponding year.
21. Now in the “deacoastlines_output” folder in the lefthand panel, select the two output
files. Right click and select “Download”. Save these on your computer for later
analysis using Excel.
How to plot the data (if you are running out of time during Week 6 you can continue
this in your own time)
22. To analyse this data, you will need to import (open) the .csv file in Excel and save as
.xlsx. Head to Microsoft help (here) for a guide. If you get stuck, ask your tutor for
assistance. In Weeks 7 and 8 we will learn how to plot data in Excel.
23. First, create a timeseries plot of the Narrabeen transect data (data in figure above)
with time on the X axis (horizontal) and annual values of each transect on the Y axis
(vertical). This will be like the plot at the bottom of the previous page (see above
timeseries figure as a guide).
Second, for a second figure calculate the anomaly in shoreline position (i.e., different
above and below the mean transect width value). This will give you positive values
when the beach had widths above average, and negative values when the beach had
widths below average (see below figure as an example).
This will also help when comparing different transects because they will all be centred
on 0 on the Y axis. To do this you need to calculate the average shoreline position
for the whole transect and then subtract this value from every year. In your own time
(and for your Individual Report) repeat this for each of the transects for your two
GEOS2115/2915 Geocoastal Research Group
Coastal Datasets Practical – Week 6 School of Geosciences, The University of Sydney
Dr Ana da Silva and Dr Tommy Fellowes
2024 8 of 13
beaches. In the example plot below we can see that the over shoreline trend is stable
(i.e., no long-term erosion or growth) but we can see a multi-year trend when the
beach was wider (e.g., 2008 – 2014) and when it was narrower (e.g., 2017 – 2021).
What might be causing this multi-year oscillation in the shorelines?
NB: If you get stuck with how to make plots, ask your tutor for assistance. These plots will
become part of your analysis included in your Individual Report.
Questions to get you thinking for your Individual Report:
• What are the annual shoreline trends at Narrabeen?
• Can you see any clear changes between the 1980s and now?
• Is the shoreline behaving the same along the full length of the beach?
End of Part A.
GEOS2115/2915 Geocoastal Research Group
Coastal Datasets Practical – Week 6 School of Geosciences, The University of Sydney
Dr Ana da Silva and Dr Tommy Fellowes
2024 9 of 13
Part B: CoastSat Shorelines (estimated time: 15 to 30 minutes)
CoastSat is an open-source software toolkit written in Python that enables the user to obtain
time-series of shoreline position at any sandy coastline worldwide from 30+ years (and
growing) of publicly available satellite imagery.
The toolkit exploits the capabilities of Google Earth Engine to efficiently retrieve Landsat and
Sentinel-2 images cropped to any user-defined region of interest. The resulting images are
pre-processed to remove cloudy pixels and enhance spatial resolution, before applying a
robust and generic shoreline detection algorithm. Like the DEA Coastline data, the purpose
of CoastSat is to provide coastal managers, engineers and scientists a user-friendly and
practical toolkit to monitor and explore their coastlines. The software is freely available on
GitHub (here). The CoastSat methodology and details about its development is presented
in Vos et al. (2019) (Link to paper).
Comparisons between DEA Coastlines and CoastSat shorelines
• DEA Coastlines provides a single mean shoreline position from annual composite
imagery. It represents the mean location for that year.
• CoastSat generates a comprehensive time-series of shoreline data from all
available satellite imagery (approx. monthly) with multiple shorelines per year.
Consider the benefits of using either annual or weekly-monthly shoreline data. Whether
you're studying short-term changes, like storm impacts, or long-term trends resulting from
coastal interventions over years to decades, a thorough grasp of shoreline variability across
various timeframes provides valuable insights into coastal dynamics. This understanding is
crucial for efficiently managing erosion, accretion cycles, and other coastal processes.
GEOS2115/2915 Geocoastal Research Group
Coastal Datasets Practical – Week 6 School of Geosciences, The University of Sydney
Dr Ana da Silva and Dr Tommy Fellowes
2024 10 of 13
Get the Data: CoastSat Shorelines
CoastSat has developed a user-friendly dashboard for exploring shoreline time-series data
in various locations worldwide, including the East Coast of Australia. For today's analysis
(and for the second beach to be analysed in your Individual Report), you will utilise this
readily available shoreline position dataset instead of conducting the entire shoreline
extraction process using the Python toolkit, as it is presented on Vos et al., 2019 paper.
For this more streamlined analysis, you will:
24. Head to http://coastsat.wrl.unsw.edu.au/. On the left you have the different data
layers and on the right you have a world map (Figure above).
25. Zoom in to Narrabeen Beach and ensure that the “Long-term trends + shoreline
time-series” layer is switched on in the lefthand panel. You will now see a single
white line along the length of Narrabeen beach shoreline.
26. Click on this line. A popup will be displayed. Now click “show transects”. You can
now see alongshore transects (Figure below) with red transects showing a long-
term retreat and blue showing long-term growth. You will notice that Narrabeen has
white (or ~white) cross-shore transects.
27. Click on one of the 4th transect from the north end of Narrabeen to bring up the
shoreline timeseries from 1988 to now (see figure below). The name of this transect
is “aus0206-0003”. This transect is the same location at PF1 from the beach
surveys measured since 1976.
28. Now we will download the data. Click on the “Downloads” button next to the
lefthand panel to bring up information on the right.
GEOS2115/2915 Geocoastal Research Group
Coastal Datasets Practical – Week 6 School of Geosciences, The University of Sydney
Dr Ana da Silva and Dr Tommy Fellowes
2024 11 of 13
29. At the bottom of this righthand panel you can see a guide on how to download each
transect data as a .csv. For example, http://coastsat.wrl.unsw.edu.au/time-
series/aus0206-0003/. The last part of the URL is the name of the transect.
30. When you open the transect URL it will open a webpage containing the data. To
save this data, in the loaded URL, right-click on the white space next to the data
and click “save as” and save the file to your computer ensuring you add .txt to end
of the file name.
31. The output is a comma separated file (.csv) or text file (.txt) that can be loaded into
Excel to make plots for your Independent Report. See Step 22 for more information.
32. Repeat Steps 29 to 31 for each ‘CoastSat Transects’ listed in the table below.
Narrabeen
DEA Transects CoastSat Transect
PF1 aus0206-0003
PF4 aus0206-0015
PF8 aus0206-0034
How to plot the data (if you are running out of time during Week 6 you can continue this in
your own time)
33. As for the DEA Coastlines data, follow Step 23 and 24 to plot this data. For the
CoastSat transect data you will need to merge the transect files downloaded in Step
29 above, so you have all 3 transects in one file. In Weeks 7 and 8 we will learn how
to plot data in Excel, but have a go now… There may be ‘None’ values in the CoastSat
data shoreline datasets. Make sure you find and replace these with an empty cell.
The dates may be different between your CoastSat transects so ensure you plot them
with the correct time column.
NB: In your own time you will extract the data for the 3 transects at Narrabeen and the 3
transects at your second beach of your choosing (Curl Curl, Bondi or Maroubra). See
Appendix below for the CoastSat transects IDs.
Questions to get you thinking for your Individual Report:
• What are the near-monthly CoastSat shoreline trends at Narrabeen?
• Can you see storm impacts or an overall retreat or growth trend?
• Can you see any clear changes between the 1980s and now?
• Is the shoreline behaving the same along the full length of the beach?
End of Part B.
GEOS2115/2915 Geocoastal Research Group
Coastal Datasets Practical – Week 6 School of Geosciences, The University of Sydney
Dr Ana da Silva and Dr Tommy Fellowes
2024 12 of 13
Appendix
For your Individual Report you will need to select a second beach and extract the same
DEA Coastline and CoastSat data. DEA Coastline shapefiles (.geojson) have been provided
for you in Canvas. The below tables show the corresponding transects from both shoreline
datasets.
Narrabeen
Bondi
DEA Transects CoastSat Transect DEA Transects CoastSat Transect
PF1 aus0206-0003 PF1 aus0211-0001
PF4 aus0206-0015 PF3 aus0211-0004
PF8 aus0206-0034 PF5 aus0211-0007
Curl Curl
Maroubra
DEA Transects CoastSat Transect DEA Transects CoastSat Transect
PF1 aus0208-0002 PF1 aus0214-0000
PF3 aus0208-0006 PF3 aus0214-0003
PF5 aus0208-0010 PF5 aus0214-0008
CoastSat URLs: http://coastsat.wrl.unsw.edu.au/time-series/$TRANSECT_ID/ where,
$TRANSECT_ID is the id of the transect in the database.
For example: http://coastsat.wrl.unsw.edu.au/time-series/aus0206-0003/
GEOS2115/2915 Geocoastal Research Group
Coastal Datasets Practical – Week 6 School of Geosciences, The University of Sydney
Dr Ana da Silva and Dr Tommy Fellowes
2024 13 of 13
Literature
Relevant literature about shoreline changes worldwide:
Barnard, P. et al. 2015. Coastal Vulnerability Across the Pacific Dominated by El Niño/Southern
Oscillation. Nature Geoscience, 8, p.801-808, DOI: 10.1038/NGEO2539
Luijendijk, A., Hagenaars, G., Ranasinghe, R., Baart, F., Donchyts, G., Aarninkhof, S. 2018. The
State of the World’s Beaches. Scientific Reports, 8, 6641, p.1-11, DOI:10.1038/s41598-018-
24630-6.
Vos, K., Harley, M.D., Turner, I.L., Splinter, K.D. 2023. Pacific Shoreline Erosion and Accretion
Patterns Controlled by El Niño/Southern Oscillation. Nature Geoscience, 16, p.140-146,
https://doi.org/10.1038/s41561-022-01117-8.
Relevant literature about shoreline datasets:
Bishop-Taylor, R., Nanson, R., Sagar, S., Lymburber, L. 2021. Mapping Australia’s Dynamic
Coastline at Mean Sea Level Using Three Decades of Landsat Imagery. Remote Sensing of
Environment, 267, 112734, p.1-19, https://doi.org/10.1016/j.rse.2021.112734.
Vos, K., Splinter, K.D., Harley, M.D., Simmons, J.A., Turner, I.L. 2019. CoastSat: A Google Earth
Engine-Enabled Python Toolkit to extract Shorelines from Publicly Available Satellite
Imagery. Environmental Modelling and Software, 122, 104528, p.1-7,
https://doi.org/10.1016/j.envsoft.2019.104528.
Relevant literature about the June 2016 storm event:
Mortlock, T.R., Goodwin, I.D., McAneney, J.K., Roche, K. 2017. The June 2016 Australian East
Coast Low: Importance of Wave Direction for Coastal Erosion Assessment. Water – MDPI,
9, 121, p.1-22, DOI:10.3390/w9020121.
Harley, M.D. et al. 2017. Extreme Coastal Erosion Enhanced by Anomalous Extratropical Storm
Wave Direction. Scientific Reports, 7, 6033, p.1-9, DOI:10.1038/s41598-017-05792-1.
End of Coastal Dataset Practical.
Coastal Datasets Practical – Week 6 School of Geosciences, The University of Sydney
Dr Ana da Silva and Dr Tommy Fellowes
2024 1 of 13
GEOS2115 / GEOS2915
Coastal Datasets Practical – Week 6
Today we will look at two open-access shoreline datasets. We will explore each dataset and
you will learn how to extract shoreline data from each at Narrabeen Beach. This practical is
a demonstration that gives you a working example of how to get the data, and in your own
time, you will follow the same steps to complete Narrabeen and your selected second beach
(Bondi, Maroubra or Curl Curl) for your Individual Report. That report is due in Week 9
(Friday 26th April at 11:59pm). See Canvas for more information.
NB: Today we will be using a Python Sandbox. Do not panic if you do not have coding
experience, as we will be running codes that are already written.
Part A: DEA Coastlines (estimated time: 30 to 45 minutes)
Digital Earth Australia Coastlines (https://www.dea.ga.gov.au/products/dea-coastlines)
Background
Australia has a highly dynamic coastline of over 30,000 km, with over 85% of its population
living within 50 km of the coast. This coastline is subject to a wide range of pressures,
including extreme weather and climate, sea level rise and human development.
Understanding how the coastline responds to these pressures is crucial to managing this
region, from social, environmental and economic perspectives.
The United States Geological Survey's (USGS) Landsat satellite program has been
capturing images of the Australian continent for more than 30 years. Digital Earth Australia
(DEA) Coastlines is a continental dataset that includes annual shorelines and rates of
coastal change along the entire Australian coastline from 1988 to now.
GEOS2115/2915 Geocoastal Research Group
Coastal Datasets Practical – Week 6 School of Geosciences, The University of Sydney
Dr Ana da Silva and Dr Tommy Fellowes
2024 2 of 13
The DEA Coastlines methodology is detailed in Bishop-Taylor et al. (2021) (Link to paper).
At a high level, they collect all the Landsat satellite images taken close to the median tide
level from a specific year for every location around Australia. Then, they remove the bad
pixels that have clouds and other interference such as sun glare. From this, they generate
an annual median composite image, i.e., a single usable mean image from the filtered
images. Afterward, they use a complex algorithm described in the paper above to create an
annual shoreline. The overall trends and retreat/grown rates are then calculated (see below).
The applications of the unique dataset include:
• Monitoring and mapping rates of coastal erosion along the Australian coastline.
• Prioritise and evaluate the impacts of local and regional coastal management based
on historical coastline change.
• Modelling how coastlines respond to drivers of change, including extreme weather
events, sea level rise or human development.
• Supporting geomorphological studies of how and why coastlines have changed
across time.
Today (and in your Individual Report) you will focus on two DEA Coastlines Products:
• Annual shorelines represent the median or ‘most representative’ position of the
shoreline at approx. 0 m Mean Sea Level for each year since 1988 (Figure below).
• Rates of change points dataset providing robust rates of coastal change for every
30 m along Australia’s non-rocky coastlines (Figure below). The most recent annual
shoreline is used as a baseline for measuring rates of change.
• The below figure shows areas of shoreline retreat in red and areas of shoreline
growth in blue. Areas with no overall change are white.
GEOS2115/2915 Geocoastal Research Group
Coastal Datasets Practical – Week 6 School of Geosciences, The University of Sydney
Dr Ana da Silva and Dr Tommy Fellowes
2024 3 of 13
Get the data: DEA Sandbox
1. Head to https://maps.dea.ga.gov.au/#share=s-DEACoastlines&playStory=1
and click through the tour at the bottom of the screen.
2. Click the ‘Explore map data’ button and add the DEA Coastline Layer. This is found
in the ‘Sea, Ocean and Coast’ tab. Select ‘DEA Coastline’. Click done in the top
right corner of the data window.
3. In the top lefthand corner use the search bar to find Narrabeen.
4. Zoom in on the beach and you will see annual shorelines from 1988 to now.
5. Now we will extract the data from Narrabeen Beach using the same locations of the
actual beach survey transects that have been collected monthly since 1976. NB: we
will be analysing these beach profiles in the Week 7’s practical.
6. Head to https://knowledge.dea.ga.gov.au/guides/setup/Sandbox/sandbox/ to quickly
read about the DEA Sandbox portal.
7. Now head to https://app.sandbox.dea.ga.gov.au/ and create an account using your
university email address. If you already have an account, just sign in.
8. Once logged in, you will be asked to click “Start” on the blue bar at the bottom of the
page. This will build your virtual environment. This may take a few moments.
9. The panel on the lefthand side of the screen is your directory containing many
documents and scripts you can analyse the DEA data. The panel on the right is
where the Python script will be displayed (see Figure Below).
10. Double-click on the folder “Interactive_apps” listed in your lefthand directory (Figure
above).
GEOS2115/2915 Geocoastal Research Group
Coastal Datasets Practical – Week 6 School of Geosciences, The University of Sydney
Dr Ana da Silva and Dr Tommy Fellowes
2024 4 of 13
11. Then double-click to open the “Coastal_transects.ipynb” code. See Figure below for
the first part of the code).
12. At the top of the code DEA Sandbox window click the “Run” menu and select ‘Run
all Cells’ (see below).
13. This will run each section (box) in the code. An example code box (section) is
shown below. The presence of a number between the “[ ]” (in this example a 1 is
shown) means the code has been successfully run.
14. Now scroll down until you see this section of code with the map of Australia and the
DEA coastline data (Figure below). This is how we extract the data along Transects.
On the left you see the transect options and on the right is the map.
GEOS2115/2915 Geocoastal Research Group
Coastal Datasets Practical – Week 6 School of Geosciences, The University of Sydney
Dr Ana da Silva and Dr Tommy Fellowes
2024 5 of 13
Troubleshooting: If you encounter any problems with the code e.g., if it is not loading
correctly or you load the incorrect transect shapefile (.geojson), you can clear all the output
and re-run the code. To do this click the “Edit” menu at the top left of DEA Sandbox screen
and select “Clear all output”. Once cleared you can re-run the code by repeating Step 13.
15. Now to help you, we have provided you with the shapefile for the Narrabeen Beach
Transects in the file “Narrabeen_transects_V2.geojson”. This file can be found on
the Canvas page for this practical. Download the file to your computer and make
sure you save it in a place you can find it later.
Download Narrabeen Shoreline Data
16. Now we will extract the shoreline data for Narrabeen at the same location of the field
beach surveys profiles (transects) collected since 1976.
17. In the section of code shown below, input the Output Name as “Narrabeen_output”.
Then make sure you have “Distance” selected in the drop down menu. Then click
the Output File for both “Figure (.png)” and “Distance table (.csv)”. In the ‘Advanced’
section click the “Upload” button and select the “Narrabeen_transects_V2.geojson”
you just downloaded from Canvas in Step 15.
Once loaded you will see the map on the right is now zoomed in on Narrabeen. You
will also see 3 black transect lines along the length of Narrabeen (see below). These
are our transect (PF1, PF4 and PF8) numbers from north. If the transect file has
loaded correctly you will see this line of text below the map “Uploaded
'Narrabeen_Transects_V2.geojson'; no 'id' column detected, labelling transects from
0 to 2.” See troubleshooting above to fix this.
GEOS2115/2915 Geocoastal Research Group
Coastal Datasets Practical – Week 6 School of Geosciences, The University of Sydney
Dr Ana da Silva and Dr Tommy Fellowes
2024 6 of 13
NB: In the DEA Sandbox code, you will have black transect lines that are bit hard to see on
the map in the above screenshot. We have manually added red transect lines to highlight
their locations for you.
18. Now Click the big teal coloured button “Extract shoreline data”. If successful you will
see the following code:
19. This code you will see the output timeseries from the 3 transects (see below). NB: in
this figure 0 = PF1, 1 = PF4 and 2 = PF8. These are numbered from the north end
of Narrabeen (see red lines in above figure for reference). In Excel changed the
names of the transects from 0, 1, 2 to the corresponding transect names.
PF1
PF4
PF8
GEOS2115/2915 Geocoastal Research Group
Coastal Datasets Practical – Week 6 School of Geosciences, The University of Sydney
Dr Ana da Silva and Dr Tommy Fellowes
2024 7 of 13
20. To get the timeseries data, double-click on the “deacoastlines_output” folder in the
directory panel on the left. This folder will contain 2 Narrabeen files:
“Narrabeen_output.png” and “Narrabeen_output.csv”. An example of the data in the
.csv file is shown below. Each Transect will have one value for each year between
1988 and now. These values are the distance between the landward end of the
transect lines and the shoreline for the corresponding year.
21. Now in the “deacoastlines_output” folder in the lefthand panel, select the two output
files. Right click and select “Download”. Save these on your computer for later
analysis using Excel.
How to plot the data (if you are running out of time during Week 6 you can continue
this in your own time)
22. To analyse this data, you will need to import (open) the .csv file in Excel and save as
.xlsx. Head to Microsoft help (here) for a guide. If you get stuck, ask your tutor for
assistance. In Weeks 7 and 8 we will learn how to plot data in Excel.
23. First, create a timeseries plot of the Narrabeen transect data (data in figure above)
with time on the X axis (horizontal) and annual values of each transect on the Y axis
(vertical). This will be like the plot at the bottom of the previous page (see above
timeseries figure as a guide).
Second, for a second figure calculate the anomaly in shoreline position (i.e., different
above and below the mean transect width value). This will give you positive values
when the beach had widths above average, and negative values when the beach had
widths below average (see below figure as an example).
This will also help when comparing different transects because they will all be centred
on 0 on the Y axis. To do this you need to calculate the average shoreline position
for the whole transect and then subtract this value from every year. In your own time
(and for your Individual Report) repeat this for each of the transects for your two
GEOS2115/2915 Geocoastal Research Group
Coastal Datasets Practical – Week 6 School of Geosciences, The University of Sydney
Dr Ana da Silva and Dr Tommy Fellowes
2024 8 of 13
beaches. In the example plot below we can see that the over shoreline trend is stable
(i.e., no long-term erosion or growth) but we can see a multi-year trend when the
beach was wider (e.g., 2008 – 2014) and when it was narrower (e.g., 2017 – 2021).
What might be causing this multi-year oscillation in the shorelines?
NB: If you get stuck with how to make plots, ask your tutor for assistance. These plots will
become part of your analysis included in your Individual Report.
Questions to get you thinking for your Individual Report:
• What are the annual shoreline trends at Narrabeen?
• Can you see any clear changes between the 1980s and now?
• Is the shoreline behaving the same along the full length of the beach?
End of Part A.
GEOS2115/2915 Geocoastal Research Group
Coastal Datasets Practical – Week 6 School of Geosciences, The University of Sydney
Dr Ana da Silva and Dr Tommy Fellowes
2024 9 of 13
Part B: CoastSat Shorelines (estimated time: 15 to 30 minutes)
CoastSat is an open-source software toolkit written in Python that enables the user to obtain
time-series of shoreline position at any sandy coastline worldwide from 30+ years (and
growing) of publicly available satellite imagery.
The toolkit exploits the capabilities of Google Earth Engine to efficiently retrieve Landsat and
Sentinel-2 images cropped to any user-defined region of interest. The resulting images are
pre-processed to remove cloudy pixels and enhance spatial resolution, before applying a
robust and generic shoreline detection algorithm. Like the DEA Coastline data, the purpose
of CoastSat is to provide coastal managers, engineers and scientists a user-friendly and
practical toolkit to monitor and explore their coastlines. The software is freely available on
GitHub (here). The CoastSat methodology and details about its development is presented
in Vos et al. (2019) (Link to paper).
Comparisons between DEA Coastlines and CoastSat shorelines
• DEA Coastlines provides a single mean shoreline position from annual composite
imagery. It represents the mean location for that year.
• CoastSat generates a comprehensive time-series of shoreline data from all
available satellite imagery (approx. monthly) with multiple shorelines per year.
Consider the benefits of using either annual or weekly-monthly shoreline data. Whether
you're studying short-term changes, like storm impacts, or long-term trends resulting from
coastal interventions over years to decades, a thorough grasp of shoreline variability across
various timeframes provides valuable insights into coastal dynamics. This understanding is
crucial for efficiently managing erosion, accretion cycles, and other coastal processes.
GEOS2115/2915 Geocoastal Research Group
Coastal Datasets Practical – Week 6 School of Geosciences, The University of Sydney
Dr Ana da Silva and Dr Tommy Fellowes
2024 10 of 13
Get the Data: CoastSat Shorelines
CoastSat has developed a user-friendly dashboard for exploring shoreline time-series data
in various locations worldwide, including the East Coast of Australia. For today's analysis
(and for the second beach to be analysed in your Individual Report), you will utilise this
readily available shoreline position dataset instead of conducting the entire shoreline
extraction process using the Python toolkit, as it is presented on Vos et al., 2019 paper.
For this more streamlined analysis, you will:
24. Head to http://coastsat.wrl.unsw.edu.au/. On the left you have the different data
layers and on the right you have a world map (Figure above).
25. Zoom in to Narrabeen Beach and ensure that the “Long-term trends + shoreline
time-series” layer is switched on in the lefthand panel. You will now see a single
white line along the length of Narrabeen beach shoreline.
26. Click on this line. A popup will be displayed. Now click “show transects”. You can
now see alongshore transects (Figure below) with red transects showing a long-
term retreat and blue showing long-term growth. You will notice that Narrabeen has
white (or ~white) cross-shore transects.
27. Click on one of the 4th transect from the north end of Narrabeen to bring up the
shoreline timeseries from 1988 to now (see figure below). The name of this transect
is “aus0206-0003”. This transect is the same location at PF1 from the beach
surveys measured since 1976.
28. Now we will download the data. Click on the “Downloads” button next to the
lefthand panel to bring up information on the right.
GEOS2115/2915 Geocoastal Research Group
Coastal Datasets Practical – Week 6 School of Geosciences, The University of Sydney
Dr Ana da Silva and Dr Tommy Fellowes
2024 11 of 13
29. At the bottom of this righthand panel you can see a guide on how to download each
transect data as a .csv. For example, http://coastsat.wrl.unsw.edu.au/time-
series/aus0206-0003/. The last part of the URL is the name of the transect.
30. When you open the transect URL it will open a webpage containing the data. To
save this data, in the loaded URL, right-click on the white space next to the data
and click “save as” and save the file to your computer ensuring you add .txt to end
of the file name.
31. The output is a comma separated file (.csv) or text file (.txt) that can be loaded into
Excel to make plots for your Independent Report. See Step 22 for more information.
32. Repeat Steps 29 to 31 for each ‘CoastSat Transects’ listed in the table below.
Narrabeen
DEA Transects CoastSat Transect
PF1 aus0206-0003
PF4 aus0206-0015
PF8 aus0206-0034
How to plot the data (if you are running out of time during Week 6 you can continue this in
your own time)
33. As for the DEA Coastlines data, follow Step 23 and 24 to plot this data. For the
CoastSat transect data you will need to merge the transect files downloaded in Step
29 above, so you have all 3 transects in one file. In Weeks 7 and 8 we will learn how
to plot data in Excel, but have a go now… There may be ‘None’ values in the CoastSat
data shoreline datasets. Make sure you find and replace these with an empty cell.
The dates may be different between your CoastSat transects so ensure you plot them
with the correct time column.
NB: In your own time you will extract the data for the 3 transects at Narrabeen and the 3
transects at your second beach of your choosing (Curl Curl, Bondi or Maroubra). See
Appendix below for the CoastSat transects IDs.
Questions to get you thinking for your Individual Report:
• What are the near-monthly CoastSat shoreline trends at Narrabeen?
• Can you see storm impacts or an overall retreat or growth trend?
• Can you see any clear changes between the 1980s and now?
• Is the shoreline behaving the same along the full length of the beach?
End of Part B.
GEOS2115/2915 Geocoastal Research Group
Coastal Datasets Practical – Week 6 School of Geosciences, The University of Sydney
Dr Ana da Silva and Dr Tommy Fellowes
2024 12 of 13
Appendix
For your Individual Report you will need to select a second beach and extract the same
DEA Coastline and CoastSat data. DEA Coastline shapefiles (.geojson) have been provided
for you in Canvas. The below tables show the corresponding transects from both shoreline
datasets.
Narrabeen
Bondi
DEA Transects CoastSat Transect DEA Transects CoastSat Transect
PF1 aus0206-0003 PF1 aus0211-0001
PF4 aus0206-0015 PF3 aus0211-0004
PF8 aus0206-0034 PF5 aus0211-0007
Curl Curl
Maroubra
DEA Transects CoastSat Transect DEA Transects CoastSat Transect
PF1 aus0208-0002 PF1 aus0214-0000
PF3 aus0208-0006 PF3 aus0214-0003
PF5 aus0208-0010 PF5 aus0214-0008
CoastSat URLs: http://coastsat.wrl.unsw.edu.au/time-series/$TRANSECT_ID/ where,
$TRANSECT_ID is the id of the transect in the database.
For example: http://coastsat.wrl.unsw.edu.au/time-series/aus0206-0003/
GEOS2115/2915 Geocoastal Research Group
Coastal Datasets Practical – Week 6 School of Geosciences, The University of Sydney
Dr Ana da Silva and Dr Tommy Fellowes
2024 13 of 13
Literature
Relevant literature about shoreline changes worldwide:
Barnard, P. et al. 2015. Coastal Vulnerability Across the Pacific Dominated by El Niño/Southern
Oscillation. Nature Geoscience, 8, p.801-808, DOI: 10.1038/NGEO2539
Luijendijk, A., Hagenaars, G., Ranasinghe, R., Baart, F., Donchyts, G., Aarninkhof, S. 2018. The
State of the World’s Beaches. Scientific Reports, 8, 6641, p.1-11, DOI:10.1038/s41598-018-
24630-6.
Vos, K., Harley, M.D., Turner, I.L., Splinter, K.D. 2023. Pacific Shoreline Erosion and Accretion
Patterns Controlled by El Niño/Southern Oscillation. Nature Geoscience, 16, p.140-146,
https://doi.org/10.1038/s41561-022-01117-8.
Relevant literature about shoreline datasets:
Bishop-Taylor, R., Nanson, R., Sagar, S., Lymburber, L. 2021. Mapping Australia’s Dynamic
Coastline at Mean Sea Level Using Three Decades of Landsat Imagery. Remote Sensing of
Environment, 267, 112734, p.1-19, https://doi.org/10.1016/j.rse.2021.112734.
Vos, K., Splinter, K.D., Harley, M.D., Simmons, J.A., Turner, I.L. 2019. CoastSat: A Google Earth
Engine-Enabled Python Toolkit to extract Shorelines from Publicly Available Satellite
Imagery. Environmental Modelling and Software, 122, 104528, p.1-7,
https://doi.org/10.1016/j.envsoft.2019.104528.
Relevant literature about the June 2016 storm event:
Mortlock, T.R., Goodwin, I.D., McAneney, J.K., Roche, K. 2017. The June 2016 Australian East
Coast Low: Importance of Wave Direction for Coastal Erosion Assessment. Water – MDPI,
9, 121, p.1-22, DOI:10.3390/w9020121.
Harley, M.D. et al. 2017. Extreme Coastal Erosion Enhanced by Anomalous Extratropical Storm
Wave Direction. Scientific Reports, 7, 6033, p.1-9, DOI:10.1038/s41598-017-05792-1.
End of Coastal Dataset Practical.
