def indexToWorld(flatmap_index, map_width, map_resolution, map_origin = [0,0]):
    """
    Converts a flatmap index value to world coordinates (meters)
    flatmap_index: a linear index value, specifying a cell/pixel in an 1-D array
    map_width: number of columns in the occupancy grid
    map_resolution: side lenght of each grid map cell in meters
    map_origin: the x,y position in grid cell coordinates of the world's coordinate origin
    Returns a list containing x,y coordinates in the world frame of reference
    """
    # convert to x,y grid cell/pixel coordinates
    grid_cell_map_x = flatmap_index % map_width
    grid_cell_map_y = flatmap_index // map_width
    # convert to world coordinates
    x = map_resolution * grid_cell_map_x + map_origin[0]
    y = map_resolution * grid_cell_map_y + map_origin[1]

    return [x,y]