Specifying choropleth layer ID
To create a choropleth map in an interactive map visual, you must specify a choropleth Layer ID.
When you request for a custom style from Mapbox, make sure that this style has a choropleth shape file in it. This shape file has the choropleth Layer ID, which is the name of a unique layer within the Custom Mapbox style that identifies the shapes that you would like to color by a measure in your data. See Custom mapbox style.
To create a choropleth map in an Interactive Map visual, you need a Custom Mapbox style and a Layer ID.