Producing Buffer Radius Polygons - Possible Projection Issue

Question

I created a GeoDataFrame with a Points geometry column:

1. Create df

df = pd.DataFrame([[51.502687, -3.538329, 2242, 1, 47],
                   [52.699185, -0.050122, 870, 2, 35],
                   [51.574387, 0.397882, 651, 3, 47],
                   [51.43874, 0.395791, 625, 4, 35],
                   [51.23965, 0.561919, 614, 5, 36]],
                   columns = ["lat","long","num_of_trucks","performance","num_of_routes"]
                 )

df 

2. Create gdf from df

gdf = gpd.GeoDataFrame(df, geometry=gpd.points_from_xy(df["lat"],df["long"]),
                                                                 crs={"init": "epsg:4326"})
gdf

3. Reproject to CRS that uses metres and calculate 10KM buffer_radius around each Point

gdf.to_crs(epsg=3395,inplace=True)
#gdf.to_crs(epsg=3857,inplace=True)
#gdf.to_crs(epsg=27700,inplace=True)

gdf["buffer_radius"] = gdf.geometry.buffer(10000)

4. Change Geometry column to new buffer_radius column

gdf = gdf.set_geometry('buffer_radius')
gdf.geometry.name

Out: 'buffer_radius'

The above process appeared to produce my desired GeoDataFrame gdf with a new "geometry" column called buffer_radius that contains Polygons.

I then wanted to plot these newly created Polygons, so first I converted the CRS of the buffer_radius column:

5. Reproject to CRS that allows me to produce plot:

gdf.to_crs(epsg=4326,inplace=True)

6. Produce final plot:

I then tried to plot the polygons however it returned an empty plot:

gv.Polygons(gdf)

The fact that my plot returns empty made me wonder if it was a possible projection issue?

Does anyone have any idea what I am doing wrong here? Any thoughts or pointers would be massively appreciated.

Thanks

Answer 1

This is apparently an issue with geoviews , which instead of using the active geometry column uses the default column called geometry . If you just override geometry column with your buffer ( gdf["geometry"] = gdf.geometry.buffer(10000) ) or make sure that the dataframe you want to plot has the geometry you want in geometry column, it should work.