def dms_to_decimal(degrees, minutes, seconds, hemisphere):
    """
    Convert from degrees, minutes, seconds to decimal degrees.
    @author: mprins
    """
    dms = float(degrees) + float(minutes) / 60 + float(seconds) / 3600
    if hemisphere in 'WwSs':
        dms = -1 * dms
    return dms
