Utility function to check if a coordinates is valid
validateCoords(lng, lat, funcName, warn = TRUE, mode = c("point", "polygon"))vector with longitude values
vector with latitude values
Name of calling function
A boolean. Whether to generate a warning message if there are rows with missing/invalid data
if "point" then warn about any NA lng/lat values;
if "polygon" then NA values are expected to be used as
polygon delimiters