Python Bokeh – Visualizing the Iris Dataset

Bokeh is a Python interactive data visualization. It renders its plots using HTML and JavaScript. It targets modern web browsers for presentation providing elegant, concise construction of novel graphics with high-performance interactivity.

Bokeh can be used to visualize the Iris flower dataset. Visualization is be done using the plotting module. Here we will be using the Iris dataset given to us by Bokeh.

Downloading the dataset :

To download the Iris dataset run the following command on the command line :

bokeh sampledata

Alternatively, we can also execute the following Python code :

import bokeh
bokeh.sampledata.download()

Analyzing the dataset :

In the sample data provided by Bokeh, there is a file iris.csv, this is the Iris dataset. Below is a glimpse into the iris.csv file :

sepal_length    sepal_width    petal_length    petal_width    species
5.1        3.5        1.4        0.2        setosa
4.9        3        1.4        0.2        setosa
4.7        3.2        1.3        0.2        setosa
4.6        3.1        1.5        0.2        setosa
5        3.6        1.4        0.2        setosa

The dataset contains 5 attributes which are :

• sepal_length in cm
• sepal_width in cm
• petal_length in cm
• petal_width in cm
• species has 3 types of flower species :
  • setosa
  • versicolor
  • virginica

Each species has 50 records and the total entries are 150.

Visualizing the Dataset :

We will be plotting graphs to visualize the clustering of the data for all the 3 species.

Example 1 : Here will be plotting a graph with length of petals as the x-axis and breadth of petals as the y-axis.

1. Import the required modules :
   • figure, output_file and show from bokeh.plotting
   • flowers from bokeh.sampledata.iris
2. Instantiate a figure object with the title.
3. Give the names to x-axis and y-axis.
4. Plot the graphs for all the 3 species.
5. Display the model.

# importing the modules
from bokeh.sampledata.iris import flowers
from bokeh.plotting import figure, show, output_file

# file to save the model
output_file("gfg.html")

# instantiating the figure object
graph = figure(title = "Iris Visualization")

# labeling the x-axis and the y-axis
graph.xaxis.axis_label = "Petal Length (in cm)"
graph.yaxis.axis_label = "Petal Width (in cm)"

# plotting for setosa petals
x = flowers[flowers["species"] == "setosa"]["petal_length"]
y = flowers[flowers["species"] == "setosa"]["petal_width"]
color = "blue"
legend_label = "setosa petals"
graph.circle(x, y,
             color = color,
             legend_label = legend_label)

# plotting for versicolor petals
x = flowers[flowers["species"] == "versicolor"]["petal_length"]
y = flowers[flowers["species"] == "versicolor"]["petal_width"]
color = "yellow"
legend_label = "versicolor petals"
graph.circle(x, y,
             color = color,
             legend_label = legend_label)

# plotting for virginica petals
x = flowers[flowers["species"] == "virginica"]["petal_length"]
y = flowers[flowers["species"] == "virginica"]["petal_width"]
color = "red"
legend_label = "virginica petals"
graph.circle(x, y,
             color = color,
             legend_label = legend_label)

# relocating the legend table to
# avoid abstruction of the graph
graph.legend.location = "top_left"

# displaying the model
show(graph)

Output :

Example 2 : Here will be plotting a scatter plot graph with both sepals and petals with length as the x-axis and breadth as the y-axis.

1. Import the required modules :
   • figure, output_file and show from bokeh.plotting
   • flowers from bokeh.sampledata.iris
2. Instantiate a figure object with the title.
3. Give the names to x-axis and y-axis.
4. Plot the graphs for all the 3 species.
5. Display the model.

# importing the modules
from bokeh.sampledata.iris import flowers
from bokeh.plotting import figure, show, output_file

# file to save the model
output_file("gfg.html")

# instantiating the figure object
graph = figure(title = "Iris Visualization")

# labeling the x-axis and the y-axis
graph.xaxis.axis_label = "Length (in cm)"
graph.yaxis.axis_label = "Width (in cm)"

# plotting for setosa petals
x = flowers[flowers["species"] == "setosa"]["petal_length"]
y = flowers[flowers["species"] == "setosa"]["petal_width"]
marker = "circle_cross"
line_color = "blue"
fill_color = "lightblue"
fill_alpha = 0.4
size = 10
legend_label = "setosa petals"
graph.scatter(x, y,
              marker = marker,
              line_color = line_color,
              fill_color = fill_color,
              fill_alpha = fill_alpha,
              size = size,
              legend_label = legend_label)

# plotting for setosa sepals
x = flowers[flowers["species"] == "setosa"]["sepal_length"]
y = flowers[flowers["species"] == "setosa"]["sepal_width"]
marker = "square_cross"
line_color = "blue"
fill_color = "lightblue"
fill_alpha = 0.4
size = 10
legend_label = "setosa sepals"
graph.scatter(x, y,
              marker = marker,
              line_color = line_color,
              fill_color = fill_color,
              fill_alpha = fill_alpha,
              size = size,
              legend_label = legend_label)

# plotting for versicolor petals
x = flowers[flowers["species"] == "versicolor"]["petal_length"]
y = flowers[flowers["species"] == "versicolor"]["petal_width"]
marker = "circle_cross"
line_color = "yellow"
fill_color = "lightyellow"
fill_alpha = 0.4
size = 10
legend_label = "versicolor petals"
graph.scatter(x, y,
              marker = marker,
              line_color = line_color,
              fill_color = fill_color,
              fill_alpha = fill_alpha,
              size = size,
              legend_label = legend_label)

# plotting for versicolor sepals
x = flowers[flowers["species"] == "versicolor"]["sepal_length"]
y = flowers[flowers["species"] == "versicolor"]["sepal_width"]
marker = "square_cross"
line_color = "yellow"
fill_color = "lightyellow"
fill_alpha = 0.4
size = 10
legend_label = "versicolor sepals"
graph.scatter(x, y,
              marker = marker,
              line_color = line_color,
              fill_color = fill_color,
              fill_alpha = fill_alpha,
              size = size,
              legend_label = legend_label)

# plotting for virginica petals
x = flowers[flowers["species"] == "virginica"]["petal_length"]
y = flowers[flowers["species"] == "virginica"]["petal_width"]
marker = "circle_cross"
line_color = "red"
fill_color = "lightcoral"
fill_alpha = 0.4
size = 10
legend_label = "virginica petals"
graph.scatter(x, y,
              marker = marker,
              line_color = line_color,
              fill_color = fill_color,
              fill_alpha = fill_alpha,
              size = size,
              legend_label = legend_label)

# plotting for virginica sepals
x = flowers[flowers["species"] == "virginica"]["sepal_length"]
y = flowers[flowers["species"] == "virginica"]["sepal_width"]
marker = "square_cross"
line_color = "red"
fill_color = "lightcoral"
fill_alpha = 0.4
size = 10
legend_label = "virginica sepals"
graph.scatter(x, y,
              marker = marker,
              line_color = line_color,
              fill_color = fill_color,
              fill_alpha = fill_alpha,
              size = size,
              legend_label = legend_label)

# relocating the legend table to
# avoid abstruction of the graph
graph.legend.location = "top_left"

# displaying the model
show(graph)

Output :