Marine Trackline Geophysical Map: NOAA Survey Routes Worldwide

This interactive map displays marine geophysical survey tracklines from NOAA’s National Geospatial Data Asset (NGDA) Marine Trackline Geophysical Database. Each line represents the route of a research vessel or aircraft that collected geophysical data — bathymetry, gravity, magnetics, seismics, or aeromagnetic measurements — from 1939 to the present. Coverage is worldwide. Use the survey type filter to explore different data collection methods.

Explore Marine Survey Tracklines

Select a survey type using the buttons above the map, then click any trackline to see the survey vessel, institution, year, and project details.

How to Use This Map

Switching Survey Types

Use the Survey Type buttons to switch between data collection methods. Each button loads a different set of tracklines from the NOAA database. Bathymetry is shown by default as it has the most extensive global coverage.

Clicking a Trackline

Click any line on the map to open a popup with details about that survey, including the vessel name, institution, country, year, and project. Where available, a link to request the raw survey data is also shown.

Share This View

The URL updates as you pan and zoom, so you can copy and share any specific view from your browser address bar.

What Is the Marine Trackline Geophysical Database?

The NOAA Marine Trackline Geophysical Database is a global archive of ship-borne and airborne geophysical measurements collected during marine research cruises from 1939 to the present. Each trackline represents the route taken by a vessel or aircraft while recording one or more types of geophysical data. The database is maintained by NOAA’s National Centers for Environmental Information (NCEI) and is part of the National Geospatial Data Asset (NGDA) program.

The database is used for scientific research, resource exploration, hazard assessment, and the study of ocean basin structure and history. Individual cruise records include navigation data paired with measurements of the seafloor and subsurface.

Survey Types Explained

• Bathymetry — Measurements of ocean depth, used to map the seafloor and chart navigational hazards. Collected using echo sounders and multibeam sonar systems. Bathymetric data underpins nautical charts, tsunami modeling, and ocean circulation research.
• Gravity — Measurements of variations in Earth’s gravitational field at sea. Marine gravity data reveals subsurface density variations, helping to map sedimentary basins, crustal thickness, and tectonic features.
• Magnetics — Measurements of Earth’s magnetic field intensity along the survey route. Marine magnetic data is fundamental to understanding seafloor spreading and plate tectonics. The symmetric magnetic anomaly patterns on either side of mid-ocean ridges provided key evidence for the theory of plate tectonics.
• Seismics — Records of acoustic energy reflected from sub-seafloor layers, used to image sediment structure and basement rock. Includes multi-channel seismics, single-channel seismics, seismic refraction profiles, and subbottom profiler data.
• Side Scan Sonar — Acoustic imaging of the seafloor surface, producing high-resolution images of seabed texture, slope failures, and features such as sand waves and shipwrecks.
• Aeromagnetic — Magnetic field measurements collected from aircraft rather than ships, covering large areas rapidly. Used extensively for geological mapping and mineral exploration, particularly in coastal and continental shelf regions.

Data Sources and Coverage

Data is sourced from the NOAA NCEI Marine Trackline Geophysical Data archive, published as a National Geospatial Data Asset under the NGDA Elevation Theme. The dataset is served via an Esri federal feature service that is updated weekly from the NOAA source.

Coverage spans all ocean basins and many coastal and shelf areas. Earlier data (pre-1970) is concentrated along routes of major oceanographic expeditions. More recent decades show denser global coverage as research vessel activity increased and data collection became routine practice on many voyages.

Frequently Asked Questions

What do the tracklines represent?

Each line shows the path a ship or aircraft took while collecting geophysical measurements. The trackline is the navigation record — the actual data values (depth readings, gravity measurements, etc.) were recorded at regular intervals along that path and are stored in the NOAA archive.

How can I download the underlying data?

Click any trackline on the map to open the survey popup. If a download link is available, it will appear at the bottom of the popup as “Request survey data.” You can also browse and download data directly from the NOAA NCEI Marine Trackline Geophysical Data portal.

Why are some ocean areas more densely covered than others?

Coverage reflects the history of oceanographic research activity. The North Atlantic, North Pacific, and US coastal waters are densely covered due to decades of US and European research programs. Remote areas of the Southern Ocean and parts of the Indian Ocean have sparser coverage. Coverage has improved substantially since the 1980s as international oceanographic programs expanded.

What is NOAA NCEI?

NOAA’s National Centers for Environmental Information (NCEI) is one of the world’s largest providers of atmospheric, coastal, geophysical, and oceanic data. NCEI manages and provides access to more than 37 petabytes of atmospheric, coastal, geophysical, and oceanic data. The Marine Trackline Geophysical Database is one of many long-running archives maintained by NCEI.

What is the NGDA program?

The National Geospatial Data Asset (NGDA) program identifies nationally significant geospatial datasets and promotes their standardization, maintenance, and public availability. The Marine Trackline Geophysical Database is designated as an NGDA dataset under the Elevation Theme, overseen by the Federal Geographic Data Committee (FGDC).