def getLonLatCrs(searchList):
    """get the correct names of the columns holding the coordinates
    @param header Header of the CSV
    @returns (lon, lat, crs) where lon, lat, crs are the column names
    """
    lng = None
    lat = None
    crs = None
    for t in searchList:
        if t.lower() in ('longitude', 'lon', 'long', 'lng'):
            lng = t
        if t.lower() in ('latitude', 'lat'):
            lat = t
        if t.lower() in ('crs', 'srs', 'coordinate reference systems',
            'reference systems', 'spatial reference system'):
            crs = t
    return lng, lat, crs
