Style a Bivariate Map

[jdeboer-geoplan]

Bivariate maps are occasionally useful see https://en.wikipedia.org/wiki/Bivariate_map

Is there a way to style them with mapbox gl? At the moment my plan is to include an additional attribute in my geoJSON that combines my two data points and I can use that in a property function. This is inelegant as I'd need to edit and reload my geoJSON when the user changes classifications.

Possibly this could be done with a change to property functions to take two properties

something like
{
"fill-color": {
"property": "temperature",
"bivariate-property": "population",
"stops": [
// temperature is low, population is low - blue
[{ value: 0, value2: 100}, 'blue'],
// temperature is low, population is high - cyan
[{ value: 0, value2: 10000}, 'cyan'],
//temperature is high, population is low - red
[{ value: 20, value2: 100},'red'],
//temperature is high, population is high - yellow
[{ value: 20, value2: 10000},'yellow'],
]
}
}

[jfirebaugh]

include an additional attribute in my geoJSON that combines my two data points

This is the best current solution. #4077 tracks the request for property functions that can combine multiple data properties using arbitrary arithmetic expressions.

[jdeboer-geoplan]

Ah smashing, thanks for that, I hadn't found that issue, I'll comment on that one with the bivariate map use case. thanks again great work.