Rain GeoJSON SG

Straight-forward API server to convert rain area radar images (Singapore) to GeoJSON.

• 50-km radar images: Weather.gov.sg
• 70-km radar images: MyENV apps
• Radar images are generated every 5 minutes.
• Raster image is converted to GeoJSON, pixel by pixel. From pixels to polygons.
• Polygons in GeoJSON are grouped by color/intensity into MultiPolygons. Adjacent polygons are unioned/combined.
• Intensity values are improvised to be 0-100. These may not be standard/scientific values. They are reverse-engineered from the rain intensity color scheme (Light → Moderate → Heavy).
• Only the latest GeoJSON data is cached and will updated every few minutes.

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🚧 UPDATE: GeoJSON output is not used anymore 🚧

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🚧 Current root (/) API calls runs on micro which is not very "serverless". This endpoint will be deprecated soon.

🚧 A new set of APIs have been added as /api endpoints which runs better as serverless functions.

Technicalities

Node.js and Vercel is required to run this server. These are the commands:

• npm i - install all dependencies
• npm run dev - run a development server
• npm start - run a production server
• vercel dev - runs local server

The URLs:

• / - return a basic JSON of basic information
• /now - return the GeoJSON result of latest radar image

• /api/observations - returns weather observations data (temperature, relative humidity, wind direction, etc)
• /api/rainarea - returns precipitation radar data.

Copyright/License

• Rain area radar images © Meteorological Service Singapore © National Environment Agency
• Singapore region boundary, under Singapore Open Data License
• Code under MIT.