A system for generating a map for use in the navigation of one or more vessels (1,2,3), the system comprising: one or more sensor sub-systems provided on a vessel and configured for sensing, in real-time, the presence of obstacles within a local environment of the vessel (1,2,3); a processor associated with the one or more sensor sub-systems for collecting the sensor data and configured for generating therefrom, in a serialised digital format, a real-time map of the local environment surrounding the vessel (1,2,3); data communication means between the processor and a remotely located hub, the hub in data communication with one or more remote sensing systems located remotely from the vessel sensor sub-systems; wherein, the hub is configured to collect additional sensor data from said one or more remote sensing systems and communicate the additional sensor data to the processor, and, the processor is configured on receipt of additional sensor data to generate a real-time map from the sensor data and the additional sensor data; characterised in that: the processor is configured to identify absence of obstacle data in a real-time map generated only from sensor data collected by the vessel's sensor subsystems and communicate data representative of the location of interest to the hub; the hub is configured to be responsive to said location of interest to identify a remote sensing system positioned to collect additional sensor data in said location of interest and communicate the additional sensor data to the processor; and the processor is configured on receipt of the additional sensor data to mesh a real-time map generated from the additional sensor data with a real-time map generated from the sensor data collected by the vessel's sensor sub-systems. one or more sensor sub-systems provided on a vessel and configured for sensing, in real-time, the presence of obstacles within a local environment of the vessel (1,2,3); a processor associated with the one or more sensor sub-systems for collecting the sensor data and configured for generating therefrom, in a serialised digital format, a real-time map of the local environment surrounding the vessel (1,2,3); data communication means between the processor and a remotely located hub, the hub in data communication with one or more remote sensing systems located remotely from the vessel sensor sub-systems; wherein, the hub is configured to collect additional sensor data from said one or more remote sensing systems and communicate the additional sensor data to the processor, and, the processor is configured on receipt of additional sensor data to generate a real-time map from the sensor data and the additional sensor data; characterised in that: the processor is configured to identify absence of obstacle data in a real-time map generated only from sensor data collected by the vessel's sensor subsystems and communicate data representative of the location of interest to the hub; the hub is configured to be responsive to said location of interest to identify a remote sensing system positioned to collect additional sensor data in said location of interest and communicate the additional sensor data to the processor; and the processor is configured on receipt of the additional sensor data to mesh a real-time map generated from the additional sensor data with a real-time map generated from the sensor data collected by the vessel's sensor sub-systems. the processor is configured to identify absence of obstacle data in a real-time map generated only from sensor data collected by the vessel's sensor subsystems and communicate data representative of the location of interest to the hub; the hub is configured to be responsive to said location of interest to identify a remote sensing system positioned to collect additional sensor data in said location of interest and communicate the additional sensor data to the processor; and the processor is configured on receipt of the additional sensor data to mesh a real-time map generated from the additional sensor data with a real-time map generated from the sensor data collected by the vessel's sensor sub-systems.