使用 plotly 绘制地理熊猫 dataframe

Question

I have a geopandas dataframe, which consists of the region name( District ), the geometry column, and the amount column. My goal is to plot a choropleth map using the method mentioned below https://plotly.com/python/choropleth-maps/#using-geopandas-data-frames

Here's a snippet of my dataframe

I also checked that my columns were in the right format/type.

And here's the code I used to plot the map

fig = px.choropleth(merged,

                   geojson=merged.geometry,

                   locations=merged.index,

                   color="Amount")

fig.update_geos(fitbounds="locations", visible=False)

fig.show()

It produced the below figure

which is obviously not the right figure. For some reasons, it doesn't show the map, instead it shows a line and when I zoom in, I am able to see the map but it has lines running through it. Like this

Has anyone ran into a similar problem? If so how were you able to resolve it?

The Plotly version I am using is 4.7.0. I have tried upgrading to a most recent version but it still didn't work.

Any help is greatly appreciated. Please find my code and the data on my github .

Answer 1

I'll give you the answer to @tgrandje's comment that solved the problem. Thanks to @Poopah and @tgrandje for the opportunity to raise the answer.

import pandas as pd
import plotly.express as px
import geopandas as gpd
import pyproj

# reading in the shapefile
fp = "./data/"
map_df = gpd.read_file(fp)
map_df.to_crs(pyproj.CRS.from_epsg(4326), inplace=True)

df = pd.read_csv("./data/loans_amount.csv")
# join the geodataframe with the cleaned up csv dataframe
merged = map_df.set_index('District').join(df.set_index('District'))
#merged = merged.reset_index()
merged.head()

fig = px.choropleth(merged, geojson=merged.geometry, locations=merged.index, color="Amount")
fig.update_geos(fitbounds="locations", visible=False)

fig.show()

Answer 2

Another possible source of the problem (when using Plotly graph_objects) is mentioned in this answer over at gis.stackexchange.com:

1. The locations argument has to point to a column that matches GeoJSON's 'id's.
2. The geojson argument expects a dictionary.

To solve your problem, you should: (i) point locations to the dataframe's index, and (ii) turn your GeoJSON string to a dictionary.

It's not exactly the answer to your question, but I thought my problem was the same as yours and this helped me. So I am including the answer here.