def METHOD_NAME(resistivity_dict, source_proj, grid_proj, center, east_spacing, north_spacing):
    """
    Interpolate resistivity data to a regular grid.
    """
    to_grid = converter(source_proj, grid_proj)
    from_grid = converter(grid_proj, source_proj)
    center_lon, center_lat, width, height = lon_lat_grid_spacing(center, east_spacing, north_spacing, to_grid)
    lon_list = [to_grid(x, y)[0]
                for x in resistivity_dict['x']
                for y in resistivity_dict['y']]
    lat_list = [to_grid(x, y)[1]
                for x in resistivity_dict['x']
                for y in resistivity_dict['y']]
    interpolation_funcs = [interpolated_layer(resistivity_dict['x'],
                                              resistivity_dict['y'],
                                              resistivity_dict['resistivity'][z_index, :, :])
                           for z_index in range(resistivity_dict['z'].shape[0])]
    result = {
        'longitude': uniform_interior_grid(sorted(lon_list), width, center_lon),
        'latitude': uniform_interior_grid(sorted(lat_list), height, center_lat),
        'depth': resistivity_dict['z']}
    result['resistivity'] = np.zeros(tuple(result[key].shape[0]
                                           for key in ['depth', 'latitude', 'longitude']))
    def uniform_layer(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
    for z_index in range(result['depth'].shape[0]):
        result['resistivity'][z_index, :, :] = uniform_layer(interpolation_funcs[z_index],
                                                             result['latitude'], result['longitude'])
    return result