route_pi - Great Circle and Composite Routes

[SaltyPaws]

At the moment OpenCPN does not support plotting of Great Circle and Composite Routes. According to the documentation, it requires an external application. (Great Circle and Composite Routes | Official OpenCPN Homepage)

My plan is to close this gap, by writing a plugin for OpenCPN that enables plotting of Great Circle and Composite Routes directly via the Gui. Working from the source code of existing plugins I have coded a "Hello World" plugin, with both menu and config menu to Wxformbuilder form.

Currently I am working out how to add routes to OpenCPN. I have worked my way through ocpn_plugin.h, but I could not find a direct function to enter waypoints or routes into OpenCPN.

My next approach was to use the NMEA data stream to write a route to OpenCPN. I created a pair of virtual com ports, and recorded a route exported with OpenCPN to GPS. ($GPWPL,3734.013,N,02402.569,E,003*66 etc). I then played this NMEA data stream (which I had saved to file) back to OpenCPN with VDR plugin. Unfortunately OpenCPN did not use the NMEA data to plot the route.

Other than writing the route to GPX file, which the user than manually needs to open, I am running out of ideas to add a route to OCPN from the plugin API. Dave/Nohal/SethDarth or other developers: any ideas how to implement this? Thank you for your support

My code & NMEA text file is in github: https://github.com/SaltyPaws/route_pi

[SethDart]

To my knowledge, this is not possible yet.

With 3.0 released, we can work on expanding the API to enable such features for future versions.

Maybe the new JSON feature could also help.

[SaltyPaws]

Ok No luck with the current version of the API. Does it make sense to make a feature request for this API functionality or is this something you are working on anyway? Another API feature that would be nice to have, is to extract coordinates using a mouse click (we know the cursor position, but we cant catch a mouse click in the API, can we?)

A second question, on the NMEA route: Should OCPN be able to accept the routes using NMEA, or is this also something that has not been implemented?

If this is the case, I will proceed using the GPX file export route, and I will implement direct route plotting once the API has been updated.

I have decided I will also add SAR patterns to this plugin, as that would be very similar functionality.

[SaltyPaws]

An update on the status of route_pi. I have added Vicente's formulas for great distance calculations. I have also added GPX export capability. The (unpolished) plugin is now capable of exporting great circle routes. next I will add limited circle routes. Please have a look and let me know what you think.

[SaltyPaws]

Development update: Limited circle capability has been added. The plugin is quite functional. I will do some more cleanup of the code, add loxodromic routing and issue

[JesperWe]

FYI, the next beta release will do interactive Greate Circle routing using the standard routing tool. (Available now in the master branch)

[SaltyPaws]

Plugin has been issued on the plug ins page, functionality is additional to OpenCPN's even in the new version.

[rgleason]

Pretty nice! Thank you.