METEOHACK

Team meteo.io's opengrib2 project for the 2019 METEOHACK hackathon.

Video preview: https://www.youtube.com/watch?v=K1vVnTqb87Q

What is this thing?

Most of the work here is under ./grib2class.js which is a grib2 reader written in pure JavaScript (i.e. that runs in the browser!)

To decode the MSC grib2 files (which use JPEG2000 for compression) we must include a third-party module called jpx.js. The JavaScript file is located in ./jpeg2000/jpx.min.js, downloaded from @OHIF/image-JPEG2000.

This repo offers two demos:

• one "all client-side" demo, where MSC grib2 data is fetched, decoded and plotted all in the client. This demo requires a proxy server, as the MSC's Datamart does not (yet) have CORS setup.

• one "local" demo, where MSC grib2 files are downloaded and served up locally. We decode and plot the grib2 data in the client. This demo is also available online at: https://archmoj.github.io/opengrib2/

We also built a script that scrapes the Datamart indices, building a list of URLs to grib2 files. For more info, look under ./scraper/README.md.

Prequisites

Node.js, npm and a "modern" browser.

Known limitation

• We don't draw a basemap (i.e the coastline overlay) on top of "regional" grib2 data
• We only draw one ensemble member, even though we decode them all
• Can't be exported as PNG, nor uploaded to plot.ly (like other plotly.js graphs)

How to run the "local" demo

• run npm i
• run npm run build:bundle-local-data
• run npm start

How to push the "local" demo to GitHub pages

• run npm run build:bundle-local-data
• git add build/bundle.js
• commit and push to origin/master, or make a PR ;)
• view it at: https://archmoj.github.io/opengrib2/

How to run the "all client-side" demo

• run npm i
• run npm run build:bundle-proxy-data
• run npm run proxy in one terminal tab
• run npm start in another terminal tab

How to dev this thing

• run npm i

for "local" demo:

• run NODE_ENV='local-data' npm run dev in one terminal tab
• run npm start in another terminal tab

for "all-client-side" demo:

• run NODE_ENV='proxy-data' npm run dev in one terminal tab
• run npm run proxy in a 2nd terminal tab
• run npm start in a 3rd terminal tab

How to make list of JavaScript dependencies licenses

• run npm run build:license_list

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Shoutouts to Plotly for letting us take part of this hackathon 🎉