West African coastlines rank among the most erosion-prone in the world. Along the Volta–Mono littoral (Gulf of Guinea), this vulnerability is compounded by intense anthropogenic pressure: successive port expansions at Lomé, coastal protection structures at Agbodrafo and Aného, and the sediment deficit induced by the Akosombo and Kpong dams have collectively restructured longshore sediment transport over three decades. The ongoing Marine Spatial Planning process for Togo therefore requires shoreline change indicators capable of capturing non-linear trajectories beyond standard single-parameter DSAS outputs.

The Linear Regression Rate (LRR) and End Point Rate (EPR), the two most widely used DSAS metrics, capture complementary but distinct shoreline properties. LRR integrates all available positions into a multi-date regression trend, smoothing short-term variability; EPR measures net displacement between the oldest and most recent positions, amplifying recent departures from long-term trajectory. On a densely sampled time series, their divergence constitutes evidence of non-linearity that single-parameter analysis systematically suppresses.

This study applies a 13-class combined LRR/EPR typology to 1,949 DSAS transects covering 101.3 km of the Volta–Mono shoreline, derived from a Landsat series spanning 1992–2024 with annual resolution from 2014 onward. The classification integrates shoreline state (EPR), long-term trend (LRR), and ratio R = EPR/LRR, with calibrated thresholds (stability: εs = 0.3 m/yr; severity: εsev = 2.0 m/yr). Results show 37.4% of transects under active erosion, 28.0% under active accretion, and 11.7% in transitional regimes. Notably, 27.2% receive an enriched diagnostic relative to LRR alone — including sign inversions and amplitude divergences invisible to single-indicator analysis. Moran's I (0.97 for LRR, 0.96 for EPR, p < 0.001) confirms strong spatial coherence, excluding random noise as the source of observed divergences.

In a context of relatively stable wave climate and documented anthropogenic segmentation of longshore transport, the spatial concentration of enriched diagnostics near coastal structures — consistent with updrift and downdrift morphodynamic responses — supports trajectories driven primarily by engineering interventions rather than regional forcing variability. Applied to Togo's Marine Spatial Planning framework, this typology directly guides setback line delineation, protection priority zoning, and assessment of past coastal interventions along one of West Africa's most heavily managed shorelines.