This investigation analyses the erosion degree in the coastal edge sector of Punta Couso, a granitic area in the Galician coast (NW Iberian Peninsula). For this purpose, high-resolution images were used; geomorphological parameters, such as joint density or terrain ruggedness (calculated from LiDAR data) and fieldwork information obtained with Proceq's Equotip 3 portable hardness tester. Based on this information, this research could verify that the mean joint direction is oriented to the main wave component (Western). Also, there is a negative correlation between rock hardness values and the joint density (−0.43). This correlation increases significantly when the measurements are grouped in 10 m areas since the low tidal water edge (an estimated shoreline) reaches −0.87. With this aggrupation method, the relation between rock resistance and joint density is clear. On the other hand, it is necessary to do a more detailed analysis of the rock composition, especially in granitic sectors, to improve these relationships’ understanding.KeywordsGranitic rocksCoastal geomorphologyHardness testerEquotipGalicia