Signal K•2mo ago

MigGat - I think this must be asked before but ...

I think this must be asked before but I can't find it. Is there any way to use o-chart maps with Freeboard-SK. I'm aware of all legal stuff, but thought that it could be used in AvNav via dongle, why not in Freeboard?

18 Replies

AdrianP•2mo ago

Freeboard-SK supports common vector & raster & chart sources served via the charts-plugin. Encrypted chart formats will need to be decrypted prior to being published by the charts-plugin.

Teppo Kurki•2mo ago

i have not done it, but afaik AvNav provides a RNC service on the local network. you can add that to the charts plugin as an external chart source (like you'd add google maps or similar). that will add the chart to the Signal K chart api and Freeboard will pick it up from there so AvNav does this in cooperation with o-charts, using their code for decrypting the chart data

FeadurOP•2mo ago

Thanks for the info, i will dig into it! Having that option would make Freeboard the ultimate plotter for me 😄

Teppo Kurki•2mo ago

Please share your results!

FeadurOP•2mo ago

I'm making some advances on the decrypting process, hope it will be solved today, but what formats can signalk-chart read? Specially since this are vector charts, with annotations on it

Teppo Kurki•2mo ago

see my direct message

FeadurOP•4w ago

Making some progress here! But sadly, the approach i wanted to pursue, which involved using OpenCPN for rendering, so no license was "bypassed" has turned almost impossible. Well, not impossible, but honestly quite painful to develop and and very error prone. So at this point I'm not sure if this will even be "publisheable", for legal reasons 🤷🏻‍♂️

FeadurOP•3w ago

What i ended upm doing is an unofficial clone of o-charts plugin for opencpn. It's basically the same code, but it exposes WMS and tilelayer endpoints to fetch the charts:

FeadurOP•3w ago

There's still some tweaking to do, but is already functional. For obvious reasons, i cannot publish it to the OpenCPN plugin repository, but at least with this plugin (which replaces o-charts plugin), you can get your o-charts everywhere in your network! Main caveat is that of course, OpenCPN needs to be ruhnning, even if minimized, because it HAS TO load the plugin That's the way i found to be as closed as possible to comply with the original EULA, because none of my code has anything to do with chart decryption. I'm just using what the original plugin does. That being said, my next step is to add a feature query, but i don't think Freeboard supports that, am i right? @Teppo Kurki

AdrianP•3w ago

You can add charts Freeboard-SK via a url to a WMS or WMTS server. Layers button-> charts -> + Enter the URL and select from the list.

FeadurOP•3w ago

Yup. that¡s what is shown in the screenshot It's working fine, but i also implemented an enpooint to get feature info in coordinates, alike openCpn right click -> object query My question was is Freeboard does support that kind of interaction

AdrianP•3w ago

Not familiar with opencpn. Do I assume that what you are referring to is a list of features on the chart? FSK doesn't support that for charts right now but if the returned list is geojson features then it could quite easily.

FeadurOP•2w ago

Actually I could implement and endpoint in any suitable format. The goal is simply to be able to click on let's sa a buoy or a light in the chart and get all the information that the vector chart has about it

AdrianP•2w ago

If the endpoint accepted a coordinate and returned a GeoJSON FeatureSet with each feature's properties populated with the relevant attributes, that would be a good start.

FeadurOP•2w ago

Tested with a simple maplibre implementation:

FeadurOP•2w ago

The response to: http://192.168.0.146:9012/feature-info?lat=41.20620363455549&lon=1.729670415056603&radius=0.0002 would be something like this:

{
"type": "FeatureCollection",
"features": [
  {
    "type": "Feature",
    "geometry": {
      "type": "Point",
      "coordinates": [0.00000000, 0.00000000]
    },
    "properties": {
      "feature": "LNDARE",
      "catgeo": "(3)"
    }
  },
  {
    "type": "Feature",
    "geometry": {
      "type": "Point",
      "coordinates": [0.00000000, 0.00000000]
    },
    "properties": {
      "feature": "SLCONS",
      "catgeo": "(3)",
      "CATSLC": "breakwater(1)",
      "NATCON": "loose boulders(3)",
      "WATLEV": "always dry(2)"
    }
  },
  {
    "type": "Feature",
    "geometry": {
      "type": "Point",
      "coordinates": [0.00000000, 0.00000000]
    },
    "properties": {
      "feature": "SLCONS",
      "catgeo": "(2)"
    }
  },
  {
    "type": "Feature",
    "geometry": {
      "type": "Point",
      "coordinates": [1.72956670, 41.20606670]
    },
    "properties": {
      "feature": "BCNLAT",
      "catgeo": "(1)",
      "BCNSHP": "beacon tower(3)",
      "CATLAM": "starboard-hand lateral mark(2)",
      "COLOUR": "green(4)",
      "OBJNAM": "AIS",
      "VERLEN": "11 m",
      "SCAMIN": "(44999)"
    }
  },
  {
    "type": "Feature",
    "geometry": {
      "type": "Point",
      "coordinates": [1.72956670, 41.20606670]
    },
    "properties": {
      "feature": "LIGHTS",
      "catgeo": "(1)",
      "COLOUR": "green(4)",
      "HEIGHT": "59.1 ft",
      "LITCHR": "FL(2)",
      "OBJNAM": "29370",
      "SIGGRP": "(2)",
      "SIGPER": " 7s",
      "SIGSEQ": "00.5+(01.5)+00.5+(04.5)",
      "VALNMR": " 5 Nm",
      "SCAMIN": "(44999)"
    }
  }
]}

{
"type": "FeatureCollection",
"features": [
  {
    "type": "Feature",
    "geometry": {
      "type": "Point",
      "coordinates": [0.00000000, 0.00000000]
    },
    "properties": {
      "feature": "LNDARE",
      "catgeo": "(3)"
    }
  },
  {
    "type": "Feature",
    "geometry": {
      "type": "Point",
      "coordinates": [0.00000000, 0.00000000]
    },
    "properties": {
      "feature": "SLCONS",
      "catgeo": "(3)",
      "CATSLC": "breakwater(1)",
      "NATCON": "loose boulders(3)",
      "WATLEV": "always dry(2)"
    }
  },
  {
    "type": "Feature",
    "geometry": {
      "type": "Point",
      "coordinates": [0.00000000, 0.00000000]
    },
    "properties": {
      "feature": "SLCONS",
      "catgeo": "(2)"
    }
  },
  {
    "type": "Feature",
    "geometry": {
      "type": "Point",
      "coordinates": [1.72956670, 41.20606670]
    },
    "properties": {
      "feature": "BCNLAT",
      "catgeo": "(1)",
      "BCNSHP": "beacon tower(3)",
      "CATLAM": "starboard-hand lateral mark(2)",
      "COLOUR": "green(4)",
      "OBJNAM": "AIS",
      "VERLEN": "11 m",
      "SCAMIN": "(44999)"
    }
  },
  {
    "type": "Feature",
    "geometry": {
      "type": "Point",
      "coordinates": [1.72956670, 41.20606670]
    },
    "properties": {
      "feature": "LIGHTS",
      "catgeo": "(1)",
      "COLOUR": "green(4)",
      "HEIGHT": "59.1 ft",
      "LITCHR": "FL(2)",
      "OBJNAM": "29370",
      "SIGGRP": "(2)",
      "SIGPER": " 7s",
      "SIGSEQ": "00.5+(01.5)+00.5+(04.5)",
      "VALNMR": " 5 Nm",
      "SCAMIN": "(44999)"
    }
  }
]}

(don't know how to paste collapsed code snippets sorry :S)

AdrianP•2w ago

wrap text in three ` for code snippet. Another option is for the client to use the WMS GetFeatureinfo request for the coordinate.... does your WMS implementation support this?

FeadurOP•2w ago

Not currently, but I can add it easily

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MigGat - I think this must be asked before but ...

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