Water Research Laboratory

CoastSat

A global shoreline mapping toolbox from publicly available satellite imagery.

CoastSat is an open-source software toolkit that enables user to obtain time-series of shoreline position at any sandy coastline worldwide from ~38 years (and growing) of publicly available satellite imagery.  

Satellite remote sensing currently offers medium-resolution (10 to 15 m) images at high temporal frequency (~5 days between images) and can provide low-cost shoreline data to coastal engineers, managers and scientists. This is often the only source of information on past shoreline changes at locations where no field measurements are available.  

The CoastSat toolkit enables the non-expert user to extract shorelines from Landsat 5, Landsat 7, Landsat 8, Landsat 9 and Sentinel-2 images. The shoreline detection algorithm implemented in CoastSat combines a sub-pixel border segmentation and an image classification component, which refines the segmentation into four distinct categories such that the shoreline detection is specific to the sand/water interface. The horizontal accuracy of the time-series of shoreline position is ~10 m. More details can be found in "CoastSat: A Google Earth Engine-enabled Python toolkit to extract shorelines from publicly available satellite imagery".

CoastSat website  

The CoastSat website provides an interactive platform to access satellite-derived shorelines obtained with CoastSat at beaches around the Pacific Rim, including Australia, California, Mexico and Hawaii. 

A couple of examples are shown below for Stockton Beach in NSW and the Tweed River Entrance bypassing system: 

Additional capabilities in our satellite remote sensing unit include: 

  • Long-term to seasonal shoreline change assessment with CoastSat and links to climate variability (ENSO)

  • Shoreline mapping from high-resolution PlanetLab cubesats (3m/pixel with daily revisits globally) to assess the impact of storm events (CoastSat.PlanetScope by Yarran Doherty) 

  • Beach slope mapping (CoastSat.slope) 

  • Monitoring of intermittent open/close estuary entrances (ICOLLS) (InletTracker by Tino Heimhuber) 

  • Small island planform dynamics (CoastSat.islands by Michael Cuttler) 

Visit the CoastSat website at coastsat.wrl.unsw.edu.au and explore the coast!