The design and application of a new data model of the coast is discussed. The data model is used for cartographic modeling in a Coastal Geographical Information System (CGIS). The model combines raster and dynamic segmentation data models to better represent the reality of the coastal zone. Same methods to cope with spatiotemporal data in CGIS, like water temperature or salinity are proposed. The data model is supported by some new operations of cartographic modeling. The use of these operations is shown in the paper.