def node_draw_size(node):
    """given a row of a nodes() dataframe, return the size it should be drawn"""

    if 'draw_size' in node.axes[0]:
        # if this value has already been calculated
        return node.draw_size

    radius = 0  # aka don't show this node by default
    if 'HoursFlooded' in node and node.HoursFlooded >= 0.083:
        radius = node.HoursFlooded * 3
    return radius