evaluation of data acquisition methodology representing morphological features of sandy beach through digital elevation model

AbstractIn the northeastern coast of Rio Grande do Norte (RN), the coastal dynamicshas been analyzed trough the multitemporal comparison of Digital Elevation Models (DEMs) generated by geodesic method based on the position and on the GNSS altimetry in relation to the Brazilian Geodesic System.That analysis has made it possible to measure the short-term morphological changes (intrannual) in regional scale. In order to validate the reliability level of the geodesic methodology, a case study has been accomplished on Soledade beach, in Macau/RN, in which the geodesic method has been compared to the topographic one by measuring distances and angles, considered as references. During the qualitative analysis, it was observed that both models demonstrated enough sensibility to represent the beach morphological features of the studied area. Quantitavely, the differences between the orthometric altitudes in relation to the standard ones have had decimeter accuracy in both models in nine external control points, with an average of -0.244m for the topographic model and 1.139m for the geodesic pattern.