Understand/Install Openplotter/OpenCPN/SignalK, I

Updated 2023-10-15 !

This post, additional posts will follow, will explain the purpose with, and quick/simple install instructions for, OpenPlotter(OP) and some other applications that can be installed with OP. 

• 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

As You investigate the different software packages You will see that there are some overlap in the functions.

With OC 5.2 + there was 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.      

To understand the purpose for respective package check the picture. 

Another more in depth explanation is found here

Install SignalK

Start with the setup described in a another post.

In OP:s "Settings" app, mark "SignalK installer" and click on "Install", at the upper right. After the install go to "Application Meny => Other => SignalK" which will open the SK GUI in Your browser.

In the upper right corner click on "Log in" and create an admin account and password. After that use the same credentials to login.

Input file/data

To be more "hands on" a, N1, sample file will be used during setup. Activate it via "Server => Connections" tab in the SK admin GUI. Fill in according to the picture with filename

/usr/lib/node_modules/signalk-server/samples/plaka.log

and click on "Apply" and then You must restart the SK server clicking on "Restart" in the upper right corner.

(It could be that the sample file is changing place in different distributions, but it can always be found with the command "sudo find / -name "plaka.log"" in a terminal/ssh session. If You also want to have AIS targets use the N2 sample file instead " /usr/lib/node_modules/signalk-server/samples/aava-n2k.data")

If You are interested in checking the raw N1 data just use 

$ cat /usr/lib/node_modules/signalk-server/samples/plaka.log

After the restart the "Dashboard" is shown with info that the selected file is processed If not check the file path.

The other picture is showing the interpreted data, in "Data Browser" tab, converted from N1 to SK format. You have to select "self" in the "Select context" drop down.

Your ship on a chart

If You have Internet connection You can check out "Your" boats progress in the south of Finland.

"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.

Next blogpost, in this series, will handle the OpenCPN setup with charts.