Forecast ETL Process

Our data source for world forecasted pollutant values is CAMS. More detail about the API can be found here

The high level ETL process is as follows:

1. Fetch list of cities in scope from the locations collection
2. Retrieve pollutant forecast data from CAMS for the next 5 days and latest forecast model
3. Use location lat/lng positions to retrieve the pollutant forecast values for each city using bilinear interpolation
4. Transform data into appropriate structure and persist each forecast into the database

Location Association Mechanism

Cities in the locations collection all contain a latitude/longitude coordinate pair indicating their location. Forecast for this specific location is calculated via bilinear interpolation on the CAMS data i.e. a weighted average of the forecast around the 4 surrounding lat/lng points of this location.