Class 12 Informatics Practices - Plotting Data using Matplotlib ( Questions and Answers) Part-1
Q1: Define visualisation.
Answer: Data visualisation means graphical or pictorial representation of the data using graph, chart, maps etc.
Q2: Name any library that is used for data visualisation in Python.
Answer: matplotlib is a python library that provides various types of data visualisation interfaces.
Q3: How does visualisation help?
Answer: Visualisation also helps to effectively communicate information to intended users.
Q4: Name sectors where data visualisation is effectively used.
Answer: Visualisation of data is effectively used in fields like health, finance, science, mathematics, engineering, etc.
Q6: What is pyplot? How is used in python program?
Answer: Pyplot is a collection of methods within matplotlib library that allows use to construct 2D plots and graphs easily and interactively.
Command used to call pyplot is:
>>> import matplotlib.pyplot as plt
Q7: Name the command to install matplotlib
Answer: pip install matplotlib
Q8: The following table lists the last week Delhi's maximum Temperature. Plot a line graph showing Temperature against date.
Date - Temperature (°C)
3/5/21 - 39
4/5/21 - 41
5/5/21 - 40
6/5/21 - 39
7/5/21 - 35
8/5/21 - 38
9/5/21 - 39
Answer:
import matplotlib.pyplot as plt
date=["3/5/21","4/5/21","5/5/21","6/5/21","7/5/21", "8/5/21", "9/5/21"]
temp=[39,41,40,39,35,38,39]
plt.plot(date, temp)
plt.show()
Q9: Modify the above program (Q8) with following changes:
(a) Set title as "May Week 2 Delhi Temperature"
(b) Set label for x-axis as "Date"
(c) Set label for y-axis as "Temperature"
(d) Show grids in the background
(e) Set marker as '*'
Answer:
import matplotlib.pyplot as plt
date=["3/5/21","4/5/21","5/5/21","6/5/21","7/5/21", "8/5/21", "9/5/21"]
temp=[39,41,40,39,35,38,39]
plt.xlabel("Date")
plt.ylabel("Temperature")
plt.title("May Week 2 Delhi Temperature")
plt.grid(True)
plt.plot(date, temp, marker='*')
plt.show()
Q10: What is the default line width?
Answer: 1 pixel (thin line)
Q11: Write a python program to show sine chart with line colour as red, line width as "4 pixels" and dashed line style.
Answer:
import matplotlib.pyplot as plt
import numpy as np
xdata = np.arange(0., 10, 0.1)
ydata = np.sin(xdata)
plt.plot(xdata, ydata, linewidth = 4, linestyle='dashed', color='red')
plt.show()
Q12: Name the function which is used to save the plot.
Answer: savefig(<filename>)
Q13: What is the purpose of a legend?
Answer: The legend of a graph reflects the data displayed in the graph's Y-axis, also called the graph series. The legend box contains small samples of each colour on the graph as well as a short description of what each colour means.
Q14: What is the purpose of title in a plot?
Answer: Title is the text that appears on the top of the plot. It defines what the chart is about.
Q15: Is it possible to show multiple plots in the same visualisation? Show with an example.
Answer: Yes multiline plots can be shown. Here follows the python snippet.
import matplotlib.pyplot as plt
import numpy as np
x = np.arange(10)
plt.plot(x, x**2)
plt.plot(x, x**3)
plt.plot(x, x*20)
plt.show()
ЁЯСЙSee Also:
Python - A Quick Revision (Q & A)
Python Snippets (Set-1)
Python Pandas (Q & A) Part-1
Python Pandas (Q & A) Part-2
Informatics Practices Sample Question Paper with Marking Scheme (2020-21)
Informatics Practices Sample Question Paper (Set-2) 2020-21
Querying and SQL Functions (Worksheet)
Important Abbreviations To Memorise
Networking (Q & A)
Networking - Data Transmission Media (Q & A)
Database Concepts (Important Terms)
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