Geographical Information Systems (GIS) in Marine Survey S. Jacob Area Manager Elcome Technologies Pvt Ltd, India Email: jacob@elcometech.com Geographical Information Systems is widely used for the land-based natural resource management, but comparatively lesser used in offshore mainly because these applications are limited by their geographic coverage or narrow focus. The data collection as input to the Marine GIS is not easy like a land based GIS. Also the parameter and methodology adopted in marine data collection is different from land based GIS system. Marine data is collected through a wide range of methods, instruments, time scales, periodicity, precision and accuracy. Marine data of different kind can be seen as spatial information layers. Several computer data bases that can be entered into a GIS are being produced by marine research institutes and governmental agencies. GIS is the most powerful tool for marine scientists to synthesize all these data for comprehensive interpretation and forecasting of marine environmental systems. Major benefit of Marine GIS includes integration of scientific and technical data, ocean use, in one geo-referenced system, a central database, and clarification and gives visual representation of ocean jurisdictions, boundaries and authorities, analysis of environmental effects and natural calamities.