title: Convert geopandas shapely polygon to geojson
body: <p>I created a circle using geopandas and it returned a shapely polygon: </p>
  
  <pre><code>POLYGON: ((...))
  </code></pre>
  
  <p>I want this same polygon as a geojson object. I ran across this:</p>
  
  <pre><code>shapely.geometry.mapping(shapelyObject)
  </code></pre>
  
  <p>which returns this:</p>
  
  <pre><code>{'type': 'Polygon', 'coordinates': (((570909.9247264927, 125477.71811034005)...}
  </code></pre>
  
  <p>But when I try to map this in mapbox it does not show anything. I think maybe it is not fully a geojson object.</p>