What an external source is drawn as, at the position of its style slot.
RASTER paints the tiles (a satellite slot), HILLSHADE shades the DEM they carry (the
elevation decoder is resolved from the source's encoding), and VECTOR merges the
source's own layers into the master tile - which is what a contour source wants, and
what addVectorDataSource is shorthand for.
What an external source is drawn as, at the position of its style slot.
RASTERpaints the tiles (a satellite slot),HILLSHADEshades the DEM they carry (the elevation decoder is resolved from the source'sencoding), andVECTORmerges the source's own layers into the master tile - which is what a contour source wants, and whataddVectorDataSourceis shorthand for.