private char getNextChar() throws IllegalArgumentException {
        if (pos == len) {
            pos++;
            return 0;
        } else if (pos > len) {
            throw new IllegalArgumentException("position after end of string");
        } else {
            return parseString.charAt(pos++);
        }
    }
The parsed longitude (degrees east if positive).
vespajlib/src/main/java/com/yahoo/geo/DegreesParser.java