code: def graph(data, src_lat, src_lon, dest_lat, dest_lon, linewidth=1, alpha=220, color='hot'):
      
      from geoplotlib.layers import GraphLayer
      _global_config.layers.append(GraphLayer(data, src_lat, src_lon, dest_lat, dest_lon, linewidth, alpha, color))
docs: Create a graph drawing a line between each pair of (src_lat, src_lon) and (dest_lat, dest_lon)
  
      :param data: data access object
      :param src_lat: field name of source latitude
      :param src_lon: field name of source longitude
      :param dest_lat: field name of destination latitude
      :param dest_lon: field name of destination longitude
      :param linewidth: line width
      :param alpha: color alpha
      :param color: color or colormap