Akin-Tunde/shoreline-nigeria

Satellite-based shoreline change analysis along the Lagos-Lekki-Badagry coast, Nigeria (2017-2025) # Shoreline Change on the Lagos–Lekki–Badagry Coast, Nigeria (2017–2025) A fully open, reproducible **DSAS-style shoreline change analysis** implemented entirely in Python. Eleven cloud-free Sentinel-2 scenes are classified into water and land with the Modified Normalised Difference Water Index and Otsu thresholding; the shoreline of each scene is recovered as a polyline; a baseline and 500 m perpendicular transects are constructed; and End Point Rates, Linear Regression Rates and Weighted Linear Regression Rates are computed per transect, with uncertainties. Author: Akinsunmi Tunde (Akin-Tunde) · Marine science graduate (B.Tech, Federal University of Technology Akure) · Licensed under the MIT License. --- ## 1 · Results at a glance **Multi-year shoreline positions.** Every extracted shoreline (2017–2025) overlaid on a satellite basemap, colour-coded by acquisition date. The smoothed black line is the median-position baseline. **Erosion and accretion hotspots.** The colour scale shows net shoreline movement between the earliest and latest scene at each transect anchor point. The strongest erosion occurs at the Lagos harbour entrance (−54 m/yr at transect 96); the strongest accretion occurs at the Tarkwa Bay sand spit (+25 m/yr at transect 90). **Alongshore rate profile.** Linear Regression Rate (red, with 90 % confidence interval) and the 12.5 km rolling median (blue dashed) along the 110.6 km study baseline. Negative values denote erosion. | Statistic (per transect) | Value | |---|---| | Transects analysed | 218 (500 m spacing over 110.6 km) | | Scenes used | 11 clear Sentinel-2 L2A scenes, 2017-05-21 → 2025-01-24 | | Median Linear Regression Rate | −1.54 m/yr | | Mean Linear Regression Rate | −1.47 m/yr (mean SE ±3.6 m/yr) | | Mean End Point Rate | −0.74 m/yr | | Mean Weighted Linear Regression Rate | −1.74 m/yr | | Eroding ( +0.5 m/yr) | 47 transects (22 %) | | Strongest erosion hotspot | −53.8 m/yr at transect 96 (Lagos harbour mouth) | | Stronges …