Python Graphs

Some tricks collected from the SO and the web

Images

How to use an image as a background

import numpy as np
import matplotlib.pyplot as plt
np.random.seed(0)
x = np.random.uniform(0.0,10.0,15)
y = np.random.uniform(0.0,10.0,15)
datafile = 'lena.jpg'
img = plt.imread(datafile)
plt.scatter(x,y,zorder=1)
plt.imshow(img, zorder=0, extent=[0.5, 8.0, 1.0, 7.0])
plt.show()

caveat This requires you know where the image corners need to be!

sources:

• Plot over an image background in python
• Adding a background image to a plot with known corner coordinates

Creating a pictogram

import matplotlib.pyplot as plt
from pywaffle import Waffle
data = {'Democratic': 48, 'Republican': 46, 'Libertarian': 3}
fig = plt.figure(
    FigureClass=Waffle, 
    rows=5, 
    values=data, 
    colors=["#232066", "#983D3D", "#DCB732"],
    legend={'loc': 'upper left', 'bbox_to_anchor': (1, 1)},
    icons='child', 
    font_size=12, 
    icon_legend=True
)
plt.show()

note:

PyWaffle supports Font Awesome icons in the chart. plotly is an alternative. Sources: - How to make a pictogram / icon chart?

Icons

Adding images to the axes of a plot

import numpy as np
import matplotlib.pyplot as plt
from matplotlib.offsetbox import OffsetImage,AnnotationBbox
def get_flag(name):
    path = "data/flags/Flags/flags/flags/24/{}.png".format(name.title())
    im = plt.imread(path)
    return im
def offset_image(coord, name, ax):
    img = get_flag(name)
    im = OffsetImage(img, zoom=0.72)
    im.image.axes = ax
    ab = AnnotationBbox(im, (coord, 0),  xybox=(0., -16.), frameon=False,
                        xycoords='data',  boxcoords="offset points", pad=0)
    ax.add_artist(ab)
countries = ["Norway", "Spain", "Germany", "Canada", "China"]
valuesA = [20, 15, 30, 5, 26]
fig, ax = plt.subplots()
ax.bar(range(len(countries)), valuesA, width=0.5,align="center")
ax.set_xticks(range(len(countries)))
ax.set_xticklabels(countries)
ax.tick_params(axis='x', which='major', pad=26)
for i, c in enumerate(countries):
    offset_image(i, c, ax)
plt.show()

• Add image annotations to bar plots

Plot images at the end of a bar chart

import matplotlib.pyplot as plt
from iso3166 import countries
import matplotlib.image as mpimg

def pos_image(x, y, pays, haut):
    pays = countries.get(pays).alpha2.lower()
    fichier = "/usr/share/iso-flags-png-320x240"
    fichier += f"/{pays}.png"
    im = mpimg.imread(fichier)
    ratio = 4 / 3
    w = ratio * haut
    ax.imshow(im,
              extent=(x - w, x, y, y + haut),
              zorder=2)

plt.style.use('seaborn')
fig, ax = plt.subplots()
liste_pays = [('France', 10), ('USA', 9), ('Spain', 5), ('Italy', 5)]
X = [p[1] for p in liste_pays]
Y = [p[0] for p in liste_pays]
haut = .8
r = ax.barh(y=Y, width=X, height=haut, zorder=1)
y_bar = [rectangle.get_y() for rectangle in r]
for pays, y in zip(liste_pays, y_bar):
    pos_image(pays[1], y, pays[0], haut)
plt.show()

and a second solution which put the flag in the axes if the bar is too short.

import numpy as np
import requests
from io import BytesIO
import matplotlib.pyplot as plt
from matplotlib.offsetbox import OffsetImage, AnnotationBbox
def offset_image(x, y, label, bar_is_too_short, ax):
    response = requests.get(f'https://www.countryflags.io/{label}/flat/64.png')
    img = plt.imread(BytesIO(response.content))
    im = OffsetImage(img, zoom=0.65)
    im.image.axes = ax
    x_offset = -25
    if bar_is_too_short:
        x = 0
    ab = AnnotationBbox(im, (x, y), xybox=(x_offset, 0), frameon=False,
                        xycoords='data', boxcoords="offset points", pad=0)
    ax.add_artist(ab)
labels = ['CW', 'CV', 'GW', 'SX', 'DO']
colors = ['crimson', 'dodgerblue', 'teal', 'limegreen', 'gold']
values = 2 ** np.random.randint(2, 10, len(labels))
height = 0.9
plt.barh(y=labels, width=values, height=height, color=colors, align='center', alpha=0.8)
max_value = values.max()
for i, (label, value) in enumerate(zip(labels, values)):
    offset_image(value, i, label, bar_is_too_short=value < max_value / 10, ax=plt.gca())
plt.subplots_adjust(left=0.15)
plt.show()

• How to show country flag at the end of the bar chart

Annotaions

Add outline arond flagged items in a plotly candlestick chart

import pandas as pd
import plotly.graph_objects as go
df = pd.DataFrame({"data_minu": ['30/10 09:00','30/10 09:05','30/10,09:10','30/10 09:15','30/10 09:20','30/10 09:25','30/10 09:30','30/10 09:35','30/10 09:40','30/10 09:45'],
                   "Open":['10','17','23','20','8','22','24','25','29','22'],
                   "High":['21','27','25','29','24','27','28','32','29','25'],
                   "Low":['6','12','18','9','5','8','24','18','15','10'],
                   "Close":['17','24','22','10','21','25','26','30','18','10'],
                   "Flag": ['0','1','1','1','0','1','1','1','0','0']})     
fig = go.Figure(data=[go.Candlestick(x=tickvals, #df['data_minu'],
                open=df['Open'], high=df['High'],
                low=df['Low'], close=df['Close'])
                     ])  
tickvals =[k*0.5 for k in range(len(df))]
ticktext=list(df["data_minu"])
fig.update_layout(xaxis_rangeslider_visible=False, xaxis_tickvals=tickvals, xaxis_ticktext=ticktext) 
for k, flag in  enumerate(df['Flag']):
    if int(flag):
        fig.add_shape(dict(type='rect',
                          xref='x', yref='y',
                          layer='below', 
                          x0 = tickvals[k]-0.2, y0 = float(df.loc[k, 'Low'])-1,
                          x1 = tickvals[k]+0.2, y1 = float(df.loc[k, 'High'])+1,
                          fillcolor='orange', #'RoyalBlue',
                          opacity=0.35))

scatterpolt with icons

library(rgdal)
library(png)

# load icons in PNG format
iconfile1 <- download.file('http://icons.iconarchive.com/icons/oxygen-icons.org/oxygen/256/Status-weather-clouds-icon.png', destfile = 'icon1.png', mode = 'wb')
icon1 <- readPNG('icon1.png')
iconfile2 <- download.file('http://icons.iconarchive.com/icons/oxygen-icons.org/oxygen/256/Status-weather-showers-scattered-icon.png', destfile = 'icon2.png', mode = 'wb')
icon2 <- readPNG('icon2.png')

# load shapefile
al <- readOGR("DZA", "DZA_adm0")

# make up some points
library(sp) 
set.seed(613) 
dat <- spsample (al, 3, type='random')

# need to offset the x/y location for the icon (depends on desired icon size)
offset <- 2
plot(al)
rasterImage(icon1, coordinates(dat)[1,1]-offset, coordinates(dat)[1,2]-offset, coordinates(dat)[1,1]+offset, coordinates(dat)[1,2]+offset)
rasterImage(icon2, coordinates(dat)[2,1]-offset, coordinates(dat)[2,2]-offset, coordinates(dat)[2,1]+offset, coordinates(dat)[2,2]+offset)
rasterImage(icon1, coordinates(dat)[3,1]-offset, coordinates(dat)[3,2]-offset, coordinates(dat)[3,1]+offset, coordinates(dat)[3,2]+offset)
points(dat)

• creating scatterplot with icons svg or png instead of points