title: How to know if there is a road in the OSM retrieved area
body: <p>I use OSMNX to retrieve driveable road within an area.</p>
  <pre><code>import osmnx as ox
  G = ox.graph_from_bbox(37.79, 37.78, -122.41, -122.43, network_type='drive')
  G_projected = ox.project_graph(G)
  ox.plot_graph(G_projected)
  
  </code></pre>
  <p>The bounding box I give may be on a road or on the sea or even in the forest. In order to distinguish between these cases, I would like to know if the reclaimed area contains at least one road. How can I do this?</p>