How to import a background image for overlay with GeoPandas

Question

I recently downloaded the shapefiles for San Francisco from Mapzen. Now I am able to display the streets, but I would like to have a real map as a background image, such that it is easier to make the link between the real roads from San Francisco and the ones shown by GeoPandas.

Here is the code to show the streets with GeoPandas:

1. First download the shapefile from Mapzen: https://s3.amazonaws.com/metro-extracts.mapzen.com/san-francisco_california.imposm-shapefiles.zip

2. Open a Python notebook and add those lines:

    #Useful starting lines
    %matplotlib inline
    import numpy as np
    import matplotlib.pyplot as plt
    %load_ext autoreload
    %autoreload 2
   

3. Load the street map:

   shapefile_dir = 'the path to your directory where you store the shapefile'

   shapefile_name ='san-francisco_california_osm_roads_gen0.shp'
   shapefile_roads = os.path.join(shapefile_dir, shapefile_name)
   

4. Import as a geopandas dataframe:

   import os
   import geopandas as gpd
   
   df = gpd.GeoDataFrame.from_file(shapefile_roads)
   

5. Simply plot the street network:

   df.plot();
   

The output should be:

Now I would like to have a real map (Color map) as a background. How can I do it?

Answer 1

After loading the data, you can use the following function to plot geographic features on live OSM map in Jupyter Notebook using Folium:

def plot_gdf_folium(gdf, center):
    m = folium.Map(center, zoom_start=10, tiles='OpenStreetMap')
    folium.GeoJson(gdf).add_to(m)
    return m

One limitation is that it doesn't work with large files, I am not quite sure what it the reason though. Note that the argument center is where the center of the resulting map is placed, for San Francisco, you may want to use: [37.784160, -122.442432].

UPDATE

To compute the center from gdf:

bo = gdf.total_bounds
center = (bo[1] + bo[3])/2, (bo[0] + bo[2])/2