- OpenCPN(OC), is the plotter software where You navigate and handle charts
- SignalK(SK), is the software where all the sensor inputs are handled. Could be NMEA data or SK formated inputs
- OpenPlotter(OP), is the administration shell where all is administrated and also handles these functions.
As You investigate the different software packages You will see that there are some overlap in the functions.
With OC 5.2 + there been several updates....
..... and the major one takes care of the earlier drawback that OC couldn’t handle the latest NMEA protocol, NMEA 2000(N2) as input. (N2 is the standard interface for all NEW navigation equipment.) The change is done so data from a SignalK server can be used as input. The input to SK could be NMEA 1803(N1), NMEA 2000(N2), sensor data from, for example Arduinos, and others, which are converted in SK to SK format which is then sent to OC.
$ cat /usr/lib/node_modules/signalk-server/samples/plaka.log
"Webapps => @Signalk/Freeboard-Sk" and then click "Center vessel" at the left menu. The chart displayed is "OpenSeaMap" which in this case is "online". Please note that there are no depths ! The Freeboard app is the SK version of a plotter, but it can just handle MBTiles charts.