def process_gps_data(gps_df, threshold_record_length=5, threshold_uplift=5):
    """
    Thin the gps data to remove stations with short record lengths and
    unrealistically high uplift or subsidence rates
    """
    gps_df = gps_df[gps_df['record_length'] > threshold_record_length]
    gps_df = gps_df[gps_df['RU(mm/yr)'] < threshold_uplift]
    gps_df = gps_df[gps_df['RU(mm/yr)'] > -threshold_uplift]
    return gps_df