title: Bokeh - get information about points that have been selected
body: <p>I have a several points that I plot into scatter plot and show in web browser window (using Bokeh).</p>
  
  <p>For selection, I use PolySelectTool or BoxSelectTool. </p>
  
  <p>There are two things I would like to do:
  1) Get information about points that have been selected in order to calculate some additional information.
  2) As points represent URLs, I would like the chart to open a new browser tab and load a particular URL whenever I click a point (representing URL).</p>
  
  <p>I don't think the code is important. But to make my question complete, here it is ...</p>
  
  <pre><code>Y = my_data
  urls = get_urls(my_data)
  
  TOOLS="pan,wheel_zoom,reset,hover,poly_select,box_select"
  p = figure(title = "My chart", tools=TOOLS)
  p.xaxis.axis_label = 'X'
  p.yaxis.axis_label = 'Y'
  
  source = ColumnDataSource(
      data=dict(
          xvals=list(Y[:,0]),
          yvals=list(Y[:,1]),
          url=urls
      )
  )
  p.scatter("xvals", "yvals",source=source,fill_alpha=0.2, size=5)
  hover = p.select(dict(type=HoverTool))
  hover.snap_to_data = False
  hover.tooltips = OrderedDict([
      ("(x,y)", "($x, $y)"),
      ("url", "@url"),
  ])
  
  select_tool = p.select(dict(type=BoxSelectTool))
  
  # 
  # I guess perhaps something should be done with select_tool
  #
  
  show(p)
  </code></pre>