Abstract: Geographic Information Systems (GIS) are an excellent tool for integrating various types of spatial information. They provide functionalities which allow for quick analysis and correlation of various types of data in a geographical context. The paper presents a Web-based GIS dedicated for integration and analysis of marine data from satellite imagery. The system operates with the use of automatic image processing procedures, which allow for detection of several different characteristics such as surface temperature or the existence and location of blooming algae. The system correlates the processing results with information from other sources, including vessel movement acquired from the Automatic Identification System, as well as results of oil spill simulation. The paper presents the architecture of the system as well as sample layers produced by the employed algorithms.