Duplicate Removal and Downsampling

[jvde-github]

When combining multiple input streams, overlapping reception can result in duplicate messages. To remove duplicates from output channels, use the experimental unique option. For example, the following removes duplicates from both console and a UDP stream:

AIS-catcher -o 1 unique on -u 127.0.0.1 5012 unique on

In JSON, set the unique key to true (remove duplicates) or false (default). Note that this could come at a performance cost that increases with the number of MMSIs so keep an eye on that.

Downsampling Options

Two additional options, position_interval and own_interval, downsample position messages and VDO messages by limiting each MMSI to at most one update per specified interval (in seconds). Both default to 0 or, equivalent, false(disabled).

Example:

AIS-catcher -u 127.0.0.1 5012 position_interval 30

Alternatively, these options are available in the Web GUI:

Thanks to user Manny for suggesting these options.

Note: These options are intended for users aggregating across multiple receivers to reduce bandwidth, and have not been optimized for large vessel counts.