character vector of layers you wish to add to the map. The
following layers are currently possible c("clouds", "cloudsClassic",
"precipitation", "precipitationClassic", "rain", "rainClassic", "snow",
"pressure", "pressureContour", "temperature", "wind").
group
the name of the group the newly created layers should belong to
(for clearGroup and addLayersControl purposes).
Human-friendly group names are permitted--they need not be short,
identifier-style names. Any number of layers and even different types of
layers (e.g. markers and polygons) can share the same group name.