def METHOD_NAME(interp_func, latitudes, longitudes):
    """
    Calculate the interpolated values for the layer.
    """
    lats, lons = latitudes.shape[0], longitudes.shape[0]
    ll_result = np.zeros((lats, lons))
    for j in range(lons):
        for i in range(lats):
            lon, lat = longitudes[j], latitudes[i]
            x, y = from_grid(lon, lat)
            ll_result[i, j] = interp_func(x, y)
    return ll_result