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