Strange Plotly behaviour with Choropleth Mapbox

Question

I want to create a choropleth map out of a GeoJSON file that looks like this:

{"type": "FeatureCollection", "features": [
{'type': 'Feature', 'geometry': {'type': 'MultiPolygon', 'coordinates': [[[[... , ...] ... [..., ...]]]]}, 'properties': {'id': 'A'},
{'type': 'Feature', 'geometry': {'type': 'MultiPolygon', 'coordinates': [[[[... , ...] ... [..., ...]]]]}, 'properties': {'id': 'B'},
...
]}

with each id property being different for each feature.

I mapped each feature (by the id property) to it's particular region as it follows:

regions = {
'A': 'MOUNTAINS',
'B': 'BEACH',
...
}

and then created a DataFrame to store each id and each region:

ids = []
for feature in geojson['features']:
  ids.append(feature['properties']['id'])
df = pd.DataFrame (ids, columns = ['id'])
df['region'] = df['id'].map(regions)

That returns a DataFrame like this:

    id         region
0   A          MOUNTAIN
1   B          BEACH
2   C          PLAIN
3   D          FOREST
...

I then tried to create a choropleth map with that info:

fig = px.choropleth_mapbox(df, geojson=geojson, color="region",
                           locations="id", featureidkey="properties.id",
                           center={"lat": -9.893, "lon": -50.423},
                           mapbox_style="white-bg", zoom=9)
fig.update_layout(margin={"r":0,"t":0,"l":0,"b":0})

However, this results in an excessively long running time, which crashes about a minute or so later, with no error.

I wanted to check if there was something wrong with the GeoJSON file and/or with the mapping, so I assigned random numeric data to each id in df, by:

df['random_number'] = np.random.randint(0,100,size=len(df))

and re-tried the map with the following code:

fig = px.choropleth_mapbox(df, geojson=geojson, color="random_number",
                           locations="id", featureidkey="properties.id",
                           center={"lat": -9.893, "lon": -50.423},
                           mapbox_style="white-bg", zoom=9)
fig.update_layout(margin={"r":0,"t":0,"l":0,"b":0})

and it worked, so I am guessing there is some kind of trouble with the non-numeric values in the region column of df, which are not being properly passed to the choropleth map.

Any advice, help or solution will be much appreciated!

Strange Plotly behaviour with Choropleth Mapbox

0 Answers