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Vessel traffic — MarineCadastre AIS

Find Automatic Identification System (AIS) vessel-track datasets, density grids, transit counts, and maritime boundary layers for U.S. waters.

What this teaches

  • The breadth of MARINECADASTRE_AIS — far more than just AIS tracks (90+ layers including boundaries, routing measures, protected areas)
  • How to scope to a specific port approach
  • Using aggregate(geometry_geohash_grid_frequency) to make a vessel-density heatmap

Source used: MARINECADASTRE_AIS

Prompt

Show me vessel traffic and AIS data covering the approaches to the Port
of Long Beach, CA. I want vessel tracks, density grids if available,
and any relevant boundary or routing layers.

Transcript

1. Scope to the port approach

search_datasets(
  collections = "MARINECADASTRE_AIS",
  bbox = "-118.5,33.6,-118.0,33.9",
  limit = 5
)

264 matching layers in the SoCal area. Top hits:

ID Title Year
mc_west_coast_ais_vessel_tracks_2011_48946 West Coast AIS Vessel Tracks 2011 2011
mc_dataset_67919 Vessel Routing Measures (IMO traffic separation, etc.) 2024
mc_u_s_state_submerged_lands_48928 U.S. State Submerged Lands (regulatory boundary) 2006

Each item links back to MarineCadastre at https://marinecadastre.gov/data/ with InPort metadata at https://www.fisheries.noaa.gov/inport/item/<id>.

2. Aggregate transit density

aggregate(
  aggregations = "geometry_geohash_grid_frequency",
  collections = "MARINECADASTRE_AIS",
  bbox = "-118.5,33.5,-117.7,34.0",
  precision = 6
)

Returns geohash buckets and counts — a heatmap of where AIS records are concentrated. At precision=6 each bucket is ~1.2 km on a side.

3. Get one tracks dataset

get_item(
  collection = "MARINECADASTRE_AIS",
  item_id = "mc_west_coast_ais_vessel_tracks_2011_48946"
)

Returns NOAA Office for Coastal Management metadata + asset URL pointing at the MarineCadastre download portal. Track data are typically distributed as zipped GeoTIFFs / GeoPackage files for desktop GIS analysis.

Result the agent gave

"For Port of Long Beach approaches:

1. Vessel tracks — annual track-line products from MarineCadastre. The 2011 West Coast tracks file (mc_west_coast_ais_vessel_tracks_2011_48946) covers the SoCal Bight including the LA / Long Beach approaches. Newer years are available — search with a datetime filter.

2. Vessel routing measures — IMO traffic separation schemes and recommended routes (mc_dataset_67919). Useful overlay for vessel-track interpretation.

3. Regulatory boundaries — U.S. State Submerged Lands and Exclusive Economic Zone polygons.

To make a density heatmap, use the aggregate query above; downstream visualization with folium or kepler.gl works well."

Variations

  • Different port: Houston (-95.5,29.5,-94.5,30.0), New York (-74.3,40.4,-73.9,40.7), Seattle (-122.5,47.5,-122.2,47.8).
  • Specific year: search with datetime = "2022-01-01T00:00:00Z/2022-12-31T23:59:59Z".
  • Beyond AIS: MarineCadastre also includes benthic habitat, offshore wind lease blocks, sediment sampling, marine mammal density. Use free-text q within the same collection.