I'm looking for a way to format/round the numerical legend labels in those maps produced by .plot()
function in GeoPandas. For example:
gdf.plot(column='pop2010', scheme='QUANTILES', k=4)
This gives me a legend with many decimal places:
I want the legend label to be integers.
As I recently encountered the same issue, and a solution does not appear to be readily available on Stack Overflow or other sites, I thought I would post the approach I took in case it is useful.
First, a basic plot using the geopandas
world map:
# load world data set
world_orig = geopandas.read_file(geopandas.datasets.get_path('naturalearth_lowres'))
world = world_orig[(world_orig['pop_est'] > 0) & (world_orig['name'] != "Antarctica")].copy()
world['gdp_per_cap'] = world['gdp_md_est'] / world['pop_est']
# basic plot
fig = world.plot(column='pop_est', figsize=(12,8), scheme='fisher_jenks',
cmap='YlGnBu', legend=True)
leg = fig.get_legend()
leg._loc = 3
plt.show()
The method I used relied on the get_texts()
method for the matplotlib.legend.Legend
object, then iterating over the items in leg.get_texts()
, splitting the text element into the lower and upper bounds, and then creating a new string with formatting applied and setting this with the set_text()
method.
# formatted legend
fig = world.plot(column='pop_est', figsize=(12,8), scheme='fisher_jenks',
cmap='YlGnBu', legend=True)
leg = fig.get_legend()
leg._loc = 3
for lbl in leg.get_texts():
label_text = lbl.get_text()
lower = label_text.split()[0]
upper = label_text.split()[2]
new_text = f'{float(lower):,.0f} - {float(upper):,.0f}'
lbl.set_text(new_text)
plt.show()
This is very much a 'trial and error' approach, so I wouldn't be surprised if there were a better way. Still, perhaps this will be helpful.