def read_locations_gpd(gdf, user_id="user_id", center="center", mapper={}):
    """
    Read locations from GeoDataFrames.

    Warps the pd.rename function to simplify the import of GeoDataFrames.

    Parameters
    ----------
    gdf : GeoDataFrame
        GeoDataFrame with valid point geometry, containing the locations to import.

    user_id : str, default 'user_id'
        name of the column storing the user_id.

    center : str, default 'center'
        name of the column storing the geometry (Center of the location).

    tz : str, optional
        pytz compatible timezone string. If None UTC is assumed.

    mapper : dict, optional
        further columns that should be renamed.

    Returns
    -------
    locs : GeoDataFrame (as trackintel locations)
        A GeoDataFrame containing the locations.

    Examples
    --------
    >>> trackintel.read_locations_gpd(df, user_id='User', center='geometry')
    """
    columns = {user_id: "user_id", center: "center"}
    columns.update(mapper)

    locs = gdf.rename(columns=columns)
    locs = locs.set_geometry("center")

    # assert validity of locations
    locs.as_locations
    return locs