Basemaps
The time-series of shoreline change provided here are derived from satellite shorelines mapped with CoastSat using publicly available imagery (Landsat Tier 1). The following limitations should be considered:
- The horizontal accuracy of the satellite-derived shorelines is 10-15 m (shoreline changes of less than 15 m cannot be resolved).
- The coverage of the Landsat collections is not homogeneous around the globe, check the Metadata layer named "Landsat Tier 1" to see how many images are available in your region of interest.
- The cross-shore transects were generated automatically, verify that the transects that you are using are shore-normal, in particular at the extremities of a beach
- The following cases may lead to erroneous data:
- Submerged reefs adjacent to the shoreline and rocky platforms
- Coastal inlets and lagoon entrances
- Shadows from cliffs or high-rise buildings on West-facing beaches (all images are taken at 10am when sun is from the east)
CoastSat Data
Click on a shoreline to visualise the transects at that beach
Click on a transect to see the time-series of shoreline change.
The shoreline trends are averaged for each beach, individual values along each transect are shown after clicking on the beach.
The methodology to obtain the shoreline time-series is described in:
Vos K., Harley M.D., Splinter K.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 & Software. 122, 104528
Click on a shoreline to visualise the transects at that beach
Click on a transect to see the time-series of shoreline change.
The beach-face slopes are averaged for each beach, individual values along each transect are shown after clicking on the beach.
The beach-face slope values in this dataset refer to the slope between MSL (Mean Sea Level) and MHWS (Mean High Water Springs).
The methodology to obtain the beach-face slope estimates is described in:
Vos K., Harley M.D., Splinter K.D., Walker A., Turner I.L. (2020). Beach slopes from satellite-derived shorelines. Geophysical Research Letters. 47(14)
Metadata
Click on the dots to popup the metadata for each location.
The Mean Springs Tidal Range was calculated from the tidal constituents as:
MSTR = 2*(M2 + S2 + K1 + O1).
The tidal constituents are extracted from the FES2014 Global tide model described in:
Carrere L., F. Lyard, M. Cancet, A. Guillot, N. Picot: FES 2014, a new tidal model - Validation results and perspectives for improvements, presentation to ESA Living Planet Conference, Prague 2016.
Click on the dots to popup the metadata for each location.
The Mean Deepwater Signicant Wave Height (Hsig) was calculated from the ERA5 reanalysis from ECMWF between 1979-2019.
Click on the dots to popup the metadata for each location.
The Relative Tidal Range (RTR) at each location is calculated as the ratio between the Mean Springs Tidal Range (MSTR) and the Significant Wave Height (Hsig).
This ratio can help determine whether a beach is:
- Wave Dominated: RTR between 0 and 3
- Tide Modified: RTR between 3 and 10
- Tide Dominated: RTR between 10 and 50
Click on the dots to popup the metadata for each location.
This layer contains the number of images available on Google Earth Engine between 1984 and 2020 from the following collections:
- Tier 1 Landsat 5, 7, 8 Top-of-Atmosphere
- Tier 2 Landsat 5, 7, 8 Top-of-Atmosphere (not recommended for time-series analysis)
- Sentinel-2 Level-1C Top-of-Atmosphere
Click on the dots to popup the metadata for each location.
This layer contains the number of images available on Google Earth Engine between 1984 and 2020 from the following collections:
- Tier 1 Landsat 5, 7, 8 Top-of-Atmosphere
- Tier 2 Landsat 5, 7, 8 Top-of-Atmosphere (not recommended for time-series analysis)
- Sentinel-2 Level-1C Top-of-Atmosphere
Click on the dots to popup the metadata for each location.
This layer contains the number of images available on Google Earth Engine between 1984 and 2020 from the following collections:
- Tier 1 Landsat 5, 7, 8 Top-of-Atmosphere
- Tier 2 Landsat 5, 7, 8 Top-of-Atmosphere (not recommended for time-series analysis)
- Sentinel-2 Level-1C Top-of-Atmosphere
Geometries (sandy beaches)
This layer contains the polygons used as region of interest to map shoreline changes with CoastSat.