Step wise area plot in matplotlib

Question

I would like to have a step-wise area plot in matplotib with pandas. I adjusted the code for a step-wise line plot but I get an error message. Here is the current code:

import pandas as pd
from matplotlib import pyplot as plt
%matplotlib inline

columns = ['Conventional control', 'Optimized control']
power_values = [[0.73,1.28], 
    [0.21, 0.21], 
    [0.18, 0.18], 
    [0.16, 1.00], 
    [0.57, 0.76], 
    [1.63, 1.62], 
    [3.28, 2.77], 
    [3.92, 0.47], 
    [3.29, 0.51], 
    [2.01, 3.64], 
    [1.72, 4.45], 
    [2.2, 0.59],
    [2.33, 4.34],
    [2.01, 2.05],
    [1.39, 1.68],
    [2.06, 0.55], 
    [3.07, 0.61], 
    [4.07, 0.61], 
    [3.66, 0.59], 
    [2.67, 0.59] ,
    [1.54, 1.65], 
    [1.37, 1.55], 
    [1.36, 0.95], 
    [1.1, 1.70],
    [0,0]] 

wind_data = pd.DataFrame(power_values, index=range(0, 25), columns=columns)
fig = plt.figure(linewidth=1, figsize=(9, 5))
ax = wind_data.plot.area(ax=plt.gca(), color =["saddlebrown", "limegreen"], stacked=False, drawstyle="steps-post"  )
ax.set_facecolor("white")
ax.set_xlabel("Time of day", fontsize = 14, labelpad=8)
ax.set_ylabel("Electrical power in kW", fontsize = 14,labelpad=8)
ax.set_xlim(0, 24)
ax.set_ylim(0, 5)



plt.xticks(wind_data.index, labels=[f'{h:02d}:00' for h in wind_data.index], rotation=90)
plt.grid(axis='y', alpha=.4)
plt.tight_layout()
hours = list(range(25)) # [0, 1, 2, ... 22, 23, 24]
labels = [f'{h:02d}:00' for h in hours] # ["00:00", "01:00", ... "23:00", "24:00"]
ax.tick_params(axis='both', which='major', labelsize=14)
ax.legend(loc='center left', bbox_to_anchor=(0.15, 1.07), fontsize = 14, ncol=3)
plt.savefig('CS_Cost_PerTimeslot.png', edgecolor='black', dpi=400, bbox_inches='tight')
plt.show()

If I do not use the argument "drawstyle="steps-post" I get just an normal area plot. But I would like to have a step-wise area plot. When using this attribut (as with the line plot) I get the error message:" AttributeError: 'PolyCollection' object has no property 'drawstyle' ". I'd be very happy if someone could help me on that. Maybe there is also another way how to tell matpoltlib not to linearly interpolate the lines between the data points.

LudvigH · Accepted Answer · 2020-03-15 18:30:28Z

2

I think the simplest way to solve your problem is to use the pyplot fill_between command directly. That way you get superb control over all the plotting elements you might want. Slightly less user friendly than the DataFrame.plot api, but still good.

Replace the line

ax = wind_data.plot.area(ax=plt.gca(), color =["saddlebrown", "limegreen"], stacked=False,drawstyle="steps-post")

with

ax=plt.gca()
for column,color in zip(wind_data.columns,['saddlebrown','limegreen']):
    ax.fill_between(
        x=wind_data.index,
        y1=wind_data[column],
        y2=0,
        label=column,
        color=color,
        alpha=.5,
        step='post',
        linewidth=2,
    )

and you're good.

answered Mar 15, 2020 at 18:30

LudvigH

4,9345 gold badges39 silver badges60 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

PeterBe Over a year ago

Thanks Ludvig for the answer

Collectives™ on Stack Overflow

Step wise area plot in matplotlib

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related