Application of the Red Relief Image Map (RRIM) in Geomorphological Analyses: Examples from Croatia

The development of LiDAR and digital elevation models has significantly improved the analysis of geomorphological forms, yet the interpretation of microrelief remains limited by standard DEM visualisations, particularly due to their dependence on illumination direction and weaker representation of concave–convex surface relationships. This study assesses the applicability of the Red Relief Image Map (RRIM) method for the interpretation of relief forms in three morphogenetically different relief types in Croatia: the tufa barriers of the Zrmanja River, the Kubarnovo brdo landslide in Hrvatska Kostajnica, and the glacial relief forms of Bilensko Mirovo. The analysis was based on a LiDAR-derived digital elevation model with a spatial resolution of 1×1 m. For each locality, hillshade, slope and RRIM visualisations were produced and compared using a qualitative comparative approach. The results show that RRIM provides the clearest representation of microrelief relationships at all analysed localities, although its advantages vary depending on geomorphological context. Overall, RRIM proved to be a valuable complementary tool for geomorphological interpretation and detailed mapping of subtle relief structures.