GMRT

The Global Multi-Resolution Topography (GMRT) synthesis is a unique and continually updated global elevation dataset. It integrates and harmonizes cleaned multibeam sonar data collected by scientists across the world’s oceans, creating a comprehensive compilation of seafloor and land elevations.

Each dataset is rigorously reviewed, processed, and gridded by the GMRT Team to ensure quality and consistency, then merged into a single, publicly available, multi-resolution compilation. As a foundational data resource for ocean science, GMRT provides seamless access to high-quality elevation data and its wide use demonstrates the enduring value of sustained investment in shared ocean data systems. The inclusion of high-resolution terrestrial elevation data makes GMRT a valuable resource for geoscientific research spanning both oceanic and terrestrial environments.

GMRT data and services are accessible through a variety of interfaces and are built into numerous applications across the ocean science and geospatial communities. GMRT has been part of the Google Earth ocean basemap since 2011 and since 2014 has contributed to the GEBCO global bathymetric grid. GMRT v4.4.0, released in August 2025, includes 43,048,817 square kilometers of curated multibeam data from 1,578 cruises.