private boolean isCompassDirection(char ch) {
        return (ch == 'N' || ch == 'S' || ch == 'E' || ch == 'W' ||
                ch == 'n' || ch == 's' || ch == 'e' || ch == 'w');
    }
parse the given string as a bounding box and return a parser object with parsed coordinates in member variables
@throws IllegalArgumentException if the input is malformed in any way
vespajlib/src/main/java/com/yahoo/geo/BoundingBoxParser.java