import logging


def nmea_lat_lon(text):
    """Method for parsing an NMEA latitude or longitude (DDDMM.MMMM) and
    converting it into decimal degrees. Only handles the numeric part, not
    any E/W or N/S component."""
    if text:
        nmea_value = float(text)
        normalized_value = nmea_value / 100
        degrees = int(normalized_value)
        if abs(degrees) >= 180.0:
            logging.warning('Improper NMEA-style latitude/longitude: "%s"', text)
            return None
        fractional_degrees = (normalized_value - degrees) / 0.60
        if abs(fractional_degrees) >= 1.0:
            logging.warning('Improper NMEA-style latitude/longitude: "%s"', text)
            return None
        return degrees + fractional_degrees
    else:
        return None