enhancement: weather from grib or forecast images

[signalk]

enhancement: weather from grib or forecast images

[panaaj]

I am looking into this. I’d like to implement this in a way that aligns with the Signal K data model so the feature works regardless of the signalk server implementation.

Something like a plugin that serves the GRIB data via a resources path which can displayed as layers on the map. For example the signalk-windjs plugin serves wind data from NOAA GRIB files as JSON from a plugin defined path rather than resources. It would good to have a plugin like this serve the data from a signalk api path instead.

It maybe worth raising this for discussion on a Slack channel.

[panaaj]

After some inital design work I have added some inital support for displaying JSON formatted GRIB data that is planned to be available in the next release as an experiment.
To display GRIB data the Signal K server will need to serve JSON output from the GRIB2JSON tool for the following paths:

• ./resources/grib: return a list of GRIB resource ids and their headers in the following format

{
	"2019101012": {
		"contents": [{
			"parameterCategory": 0,
			"parameterCategoryName": "Temperature",
			"parameterNumber": 0,
			...
			"refTime": "2019-10-10T12:00:00.000Z"
		}, {
			"parameterCategory": 2,
			"parameterCategoryName": "Momentum",
			"parameterNumber": 2,
			"parameterNumberName": "U-component_of_wind",
                      ...
                }]
          },
         "2019101018": {
               ...
         }
}

• ./resources/grib/<id>: return all contents for the selected GRIB resource id

• ./resources/grib/<id>:<sections>: return selected content sections as per the supplied <sections> list for the selected GRIB resource id.
  Note: <sections> is the zero based index of the sections required.

e.g. return 3rd section (index=2) ./resources/grib/2019101018:2

e.g. return 1st and 3rd sectios (indexes= 0 & 2) ./resources/grib/2019101018:0-2

[panaaj]

Sample of Freeboard screenshot:

[panaaj]

Release available for testing.

[panaaj]

v1.8.0 Experiment:

v1.8.0 in conjuction with the freeboard-sk-helper plugin provides the ability to serve and display JSON formatted GRIB data.

To try this out:

1. Install the freeboard-sk-helper plugin
2. In Freeboard go to the bottom of the Settings screen and check Experimental Features. This will display the GRIB (cloud icon) button on the right side of the screen.
3. Place JSON formatted GRIB data (created by the GRIB2JSON java application) in the .signalk/freeboard-sk-helper/grib folder on your Signal K server.

Clicking the GRIB data button will display the GRIB panel at the bottom of the screen where you can select a GRIB file (time) and if it contains Wind Vector and / or Temperature data to display on the map.

Note: a Zoom In prompt will appear in the GRIB panel if your current zoom level is not within the zoom range that GRIB data is displayed.

[joabakk]

Wow, this is great. Thanks a lot!