How to prevent overlapping labels in annotation in Matplotlib map?

Question

I am trying to prevent the labels in the Northeast US map below from overlapping. I have tried to turn labels on and off for certain states in the region, but there definitely is a better way of doing it. Below is my code and output.

csv = pd.read_csv(r'C:\Downloads\Data.csv')
sf = r'C:\Downloads\s_11au16\s_11au16.shp'
US = gpd.read_file(sf)

#Merge them
data = gpd.GeoDataFrame(csv.merge(US))

#set projection
data = data.to_crs(epsg=6923)

#set up basemap
ax = data.plot(figsize = (12,8), column="soil_data", cmap="Greens", edgecolor='black', linewidth=.5, vmin=0, vmax=70, 
               missing_kwds={"color": "white", "edgecolor": "k", "label": "none"})
ax.set_title("Example", fontsize=18, fontweight='bold')
ax.set_axis_off()


#annotate data
label = data.dropna(subset='soil_data')
label.apply(lambda x: ax.annotate(text=int(x['soil_data']), xy=x.geometry.centroid.coords[0], color="black", 
                                  ha='center', fontsize=14, path_effects=[pe.withStroke(linewidth=3, 
                                                                                        foreground="white")]), axis=1)

Have you tried [adjustText](https://stackoverflow.com/questions/69522503/how-do-i-achieve-non-overlapping-text-with-matplotlib-without-changing-yticks)? — Tranbi, Apr 06 '22 at 14:44
Yes @Tranbi, this was the first thing I tried. I am struggling with getting it to work. I keep getting an error "'str' object has no attribute 'get_position' ". I guess I'm just unfamiliar with where the adjustText would go in my function. — Boone, Apr 06 '22 at 15:12

score 2 · Accepted Answer · answered Apr 06 '22 at 15:49

Obviously I cannot test it without your data but if you're willing to try again with adjustText you could try replacing your label.apply(...) with something like that:

texts = []
for i, row in label.iterrows(): 
  texts.append(ax.annotate(text=int(row['soil_data']), xy=row.geometry.centroid.coords[0], color="black", 
                                  ha='center', fontsize=14, path_effects=[pe.withStroke(linewidth=3, 
                                                                                        foreground="white")]))

adjust_text(texts)

I don't know how adjust_text deals with annotations, so if this doesn't work, you could try converting it to plt.text.

(The matplotlib class Annotation inherits from the Text class)

How to prevent overlapping labels in annotation in Matplotlib map?

1 Answers1