Polygon Events

The Polygon Event API enables historical and real-time tracking of all vessels as they enter or exit defined maritime zones, such as ports, canals, anchorages, terminals, shipyards. By leveraging over 12 years of AXSMarine’s proprietary AIS data, this API provides structured insights into vessel movements across 60 000+ AXSMarine proprietary polygons.

A polygon event represents a vessel's movement through a strategically defined maritime zone, triggered when the vessel enters and exits the area. Each event is captured through two key AIS signals: entry (the first AIS signal detected within the polygon) and out (the last AIS signal before the vessel leaves the polygon), as reflected in the API response.

Key Features

🚢 Vessel Activity Insights – Identify when a vessel enters and exits a geofenced area using the first and last AIS signals within the polygon. Each “polygon event” captures both entry and exit parameters, providing a detailed snapshot of the event.

📍 Geofenced Tracking – Track vessel movements through custom-defined zones including anchorages, canals, terminals, and more using polygon-based detection.

⏱ Event Duration – Calculate time spent within the polygon to support congestion analysis or loading duration metrics.

📊 Time Series Ready – Use historical event data to generate time series charts of port activity, vessel counts, and duration.

🚨 Activity Alerts – Monitor live “open” events to trigger alerts when vessels enter specific zones or are still present within them.

🎯 Flexible Filtering – Apply filters by:

• Vessel IMO, DWT, or other specifications
• Polygon ID, name, or type (e.g., anchorage, canal)
• Entry or exit timestamps and AIS attributes
• Filtering with isOpen = true is recommended for tracking real-time vessel activity.

📚 Data Depth – Access a comprehensive archive of over 12 years of vessel tracking data, suitable for trend analysis and predictive modeling.

📦 Efficient Pagination – Handle large result sets with cursor-based pagination. Use tight filters to limit scope and improve performance.

The purpose of this API is to provide a unified response across all vertical markets that we serve. Two points need to be taken into considerations:

• Geographic location: While most geographic locations are common across all verticals (e.g. the Port of Rotterdam is identical for dry and tanker vessels), this is not the case for zone locations, which are market-dependent areas and are not shared across verticals.
• Segments filtering: This API offers greater granularity than REST APIs, which are decoupled by main verticals (dry / tanker). In contrast, this API provides a more detailed list of segments, as shown below:

Advanced Filtering

The new filter ancestorPolygons lets you target events that occur within a parent polygon (e.g., a port or broader zone).

What is ancestorPolygons?

ancestorPolygons restricts the search to events whose child polygon is inside one or more specified parent polygons. It must be used together with polygonTypes to narrow the child type (e.g., anchorage, canal, port).

Example Query

 
query GetOpenAnchorages {
  polygonEvents(
    first: 50
    isOpen: true
    polygonTypes: ["anchorage"]
    ancestorPolygons: ["NLRTM"]
  ) {
    edges {
      node {
        _id
        isOpen
        duration
        polygon { _id name type }
        vessel { imo name type segment }
        entryAis { time latitude longitude }
        outAis { time latitude longitude }
      }
      cursor
    }
    pageInfo { hasNextPage endCursor }
    totalCount
  }
}

This returns the first 50 open anchorage events that are inside the “NLRTM”(Rotterdam) parent polygons.