title: How to plot a .SHP file with Plotly go.Choroplethmapbox()?
body: <p>I need to plot a Choropleth graph on a Plotly map using a custom SHP file.</p>
  <p>SHP file  is used to get the boundary information. I convert it to geojson and feed it to Plotly but all i get is an empty base-map with no error messages.</p>
  <p>Here is what i tried:</p>
  <pre><code>import json
  import random
  import pandas as pd
  import geopandas as gpd
  import plotly.graph_objects as go
  
  # Create GeoDataFrame for SHP file
  geodf = gpd.read_file('data/postal-areas-2021/PKS_postinumeroalueet_2021_shp.shp')
  # Save as geojson
  geodf.to_file(&quot;data.geojson&quot;, encoding='utf-8', driver = &quot;GeoJSON&quot;)
  # Open the file
  with open(&quot;data.geojson&quot;, encoding='utf-8') as geofile:
      counties = json.load(geofile)
  
  # Create a new Dataframe for supplying z values(colors) to Choropleth.
  df = pd.DataFrame()
  
  # Create lists to store the values
  postal_code = []
  rand = []
  # Using Posno(Postal code) as ID and generateing random integers from 1-100 as a color value
  for i,v in enumerate(counties['features']):
      postal_code.append(counties['features'][i]['properties']['Posno'])
      rand.append(random.randint(1,100))
  
  # Adding the columns to the dataframe
  df['Posno'] = postal_code
  df['rand'] = rand
  
  # Creating the figure and assigning the values
  fig = go.Figure(go.Choroplethmapbox(geojson=counties, locations=df['Posno'], z=df['rand'],
                                      colorscale=&quot;Viridis&quot;, zmin=0, zmax=12, marker_line_width=5))
  
  fig.update_layout(mapbox_style=&quot;open-street-map&quot;,
                          height = 1000,
                          autosize=True,
                          margin={&quot;r&quot;:0,&quot;t&quot;:0,&quot;l&quot;:0,&quot;b&quot;:0},
                          paper_bgcolor='#303030',
                          plot_bgcolor='#303030',
                          mapbox=dict(center=dict(lat=60.1699, lon=24.9384),zoom=11),
                          )
  fig.show()
  </code></pre>
  <p><strong>Question:</strong>
  How to plot a choropleth from an SHP file with Plotly go.Choroplethmapbox()?</p>