Given a data object and lng/lat arguments (which may be NULL [meaning infer from data], formula [which should be evaluated with respect to the data], or vector data [which should be used as-is]) return a lng/lat data frame.
derivePoints(data, lng = NULL, lat = NULL, missingLng = missing(lng),
missingLat = missing(lat), funcName = "f")
map data
longitude
latitude
whether lng is missing
whether lat is missing
Name of calling function (for logging)