PyCon Italia 2025 ABC of the data visualization. https://2025.pycon.it/en/event/the-art-of-data-visualization

1. PyCon Italia 2025
The Art of Data
Visualization
#PyConIT2025

2. PyCon Italia 2025
Data & Automation Specialist @ Corley Cloud
alessandra.bilardi@corley.it
corley.it
Alessandra Bilardi

3. PyCon Italia 2025
Alessandra Bilardi
Data & Automation Specialist @ Corley Cloud
alessandra.bilardi@corley.it
corley.it

4. PyCon Italia 2025
Alessandra Bilardi
Data & Automation Specialist @ Corley Cloud
alessandra.bilardi@corley.it
corley.it

5. PyCon Italia 2025
SUMMARY
Data driven
EDA and plotting tools
Chart choice depending on viewer
Take away

6. PyCon Italia 2025
What are the steps
where we need to visualize the data ?

7. PyCon Italia 2025
Where we need to visualize the data ?

8. PyCon Italia 2025
Where we need to visualize the data ?
Data ingestion
● frequency
● quantity

9. PyCon Italia 2025
Which visualization to describe
whether a real time or batch
system is better ?

10. PyCon Italia 2025

11. PyCon Italia 2025

12. PyCon Italia 2025

13. PyCon Italia 2025

14. PyCon Italia 2025

15. PyCon Italia 2025
Which is the simplest ?
Bubble or line?

16. PyCon Italia 2025
Time for Some Theory: precognitive tasks
https://mammothmemory.net/

17. PyCon Italia 2025
Time for Some Theory: human perception
http://euclid.psych.yorku.ca/www/psy6135/papers/ClevelandMcGill1984.pdf

18. PyCon Italia 2025
Time for Some Theory: human perception
1. position, common scale
http://euclid.psych.yorku.ca/www/psy6135/papers/ClevelandMcGill1984.pdf
➢ scatter plot, point map

19. PyCon Italia 2025
Time for Some Theory: human perception
1. position, common scale
2. position, non-aligned
http://euclid.psych.yorku.ca/www/psy6135/papers/ClevelandMcGill1984.pdf
➢ scatter plot, point map
➢ scatter plot matrix

20. PyCon Italia 2025
Time for Some Theory: human perception
1. position, common scale
2. position, non-aligned
3. size, length
http://euclid.psych.yorku.ca/www/psy6135/papers/ClevelandMcGill1984.pdf
➢ scatter plot, point map
➢ scatter plot matrix
➢ bar chart, histogram

21. PyCon Italia 2025
Time for Some Theory: human perception
1. position, common scale
2. position, non-aligned
3. size, length
4. orientation, angle
http://euclid.psych.yorku.ca/www/psy6135/papers/ClevelandMcGill1984.pdf
➢ scatter plot, point map
➢ scatter plot matrix
➢ bar chart, histogram
➢ pie chart, gradient lines

22. PyCon Italia 2025
Time for Some Theory: human perception
1. position, common scale
2. position, non-aligned
3. size, length
4. orientation, angle
5. size, area
http://euclid.psych.yorku.ca/www/psy6135/papers/ClevelandMcGill1984.pdf
➢ scatter plot, point map
➢ scatter plot matrix
➢ bar chart, histogram
➢ pie chart, gradient lines
➢ tree map, bubble chart

23. PyCon Italia 2025
Time for Some Theory: human perception
1. position, common scale
2. position, non-aligned
3. size, length
4. orientation, angle
5. size, area
6. size, volume & brightness
http://euclid.psych.yorku.ca/www/psy6135/papers/ClevelandMcGill1984.pdf
➢ scatter plot, point map
➢ scatter plot matrix
➢ bar chart, histogram
➢ pie chart, gradient lines
➢ tree map, bubble chart
➢ 3d, heat map

24. PyCon Italia 2025
Time for Some Theory: human perception
1. position, common scale
2. position, non-aligned
3. size, length
4. orientation, angle
5. size, area
6. size, volume & brightness
7. color
http://euclid.psych.yorku.ca/www/psy6135/papers/ClevelandMcGill1984.pdf
➢ scatter plot, point map
➢ scatter plot matrix
➢ bar chart, histogram
➢ pie chart, gradient lines
➢ tree map, bubble chart
➢ 3d, heat map
➢ color hue scales

25. PyCon Italia 2025
Time for Some Theory: human perception
1. position, common scale
2. position, non-aligned
3. size, length
4. orientation, angle
5. size, area
6. size, volume & brightness
7. color
http://euclid.psych.yorku.ca/www/psy6135/papers/ClevelandMcGill1984.pdf
➢ scatter plot, point map
➢ scatter plot matrix
➢ bar chart, histogram
➢ pie chart, gradient lines
➢ tree map, bubble chart
➢ 3d, heat map
➢ color hue scales

26. PyCon Italia 2025

27. PyCon Italia 2025
Which is the simplest ?
Bubble or line?

28. PyCon Italia 2025
Time for Some Theory: human perception
1. position, common scale
2. position, non-aligned
3. size, length
4. orientation, angle
5. size, area
6. size, volume & brightness
7. color
http://euclid.psych.yorku.ca/www/psy6135/papers/ClevelandMcGill1984.pdf
➢ scatter plot, point map
➢ scatter plot matrix
➢ bar chart, histogram
➢ pie chart, gradient lines
➢ tree map, bubble chart
➢ 3d, heat map
➢ color hue scales

29. PyCon Italia 2025
Time for Some Theory: human perception
1. position, common scale
2. position, non-aligned
3. size, length
4. orientation, angle
5. size, area
6. size, volume & brightness
7. color
http://euclid.psych.yorku.ca/www/psy6135/papers/ClevelandMcGill1984.pdf
➢ scatter plot, point map
➢ scatter plot matrix
➢ bar chart, histogram
➢ pie chart, gradient lines
➢ tree map, bubble chart
➢ 3d, heat map
➢ color hue scales

30. PyCon Italia 2025

31. PyCon Italia 2025
Where we need to visualize the data ?
Data ingestion
● frequency
● quantity

32. PyCon Italia 2025
Where we need to visualize the data ?
Data ingestion
● frequency
● quantity
● data type

33. PyCon Italia 2025
Which EDA tools to use ?

34. PyCon Italia 2025
EDA tools

35. PyCon Italia 2025
EDA tools
tool correlation distribution missing version contributors
YData profiling table & heatmap * histogram bar & heatmap 4.16.1 116
dabl scatter plot histogram --- 0.3.2 25
klib table & heatmap ** line / histo bar & heatmap 1.3.1 6
PyGWalker calculated field drag & drop calculated field 0.4.9.15 23

36. PyCon Italia 2025
EDA tools
tool correlation distribution missing version contributors
YData profiling table & heatmap * histogram bar & heatmap 4.16.1 116
dabl scatter plot histogram --- 0.3.2 25
klib table & heatmap ** line / histo bar & heatmap 1.3.1 6
PyGWalker calculated field drag & drop calculated field 0.4.9.15 23
** also single feature heatmap
* also interactions

37. PyCon Italia 2025
EDA tools
tool correlation distribution missing version contributors
YData profiling table & heatmap * histogram bar & heatmap 4.16.1 116
dabl scatter plot histogram --- 0.3.2 25
klib table & heatmap ** line / histo bar & heatmap 1.3.1 6
PyGWalker calculated field drag & drop calculated field 0.4.9.15 23
** also single feature heatmap
* also interactions

38. PyCon Italia 2025
EDA tools
tool correlation distribution missing version contributors
YData profiling table & heatmap * histogram bar & heatmap 4.16.1 116
dabl scatter plot histogram --- 0.3.2 25
klib table & heatmap ** line / histo bar & heatmap 1.3.1 6
PyGWalker calculated field drag & drop calculated field 0.4.9.15 23
** also single feature heatmap
* also interactions

39. PyCon Italia 2025
EDA tools
tool correlation distribution missing version contributors
YData profiling table & heatmap * histogram bar & heatmap 4.16.1 116
dabl scatter plot histogram --- 0.3.2 25
klib table & heatmap ** line / histo bar & heatmap 1.3.1 6
PyGWalker calculated field drag & drop calculated field 0.4.9.15 23
** also single feature heatmap
* also interactions

40. PyCon Italia 2025
EDA tools
tool correlation distribution missing version contributors
YData profiling table & heatmap * histogram bar & heatmap 4.16.1 116
dabl scatter plot histogram --- 0.3.2 25
klib table & heatmap ** line / histo bar & heatmap 1.3.1 6
PyGWalker calculated field drag & drop calculated field 0.4.9.15 23
** also single feature heatmap
* also interactions

41. PyCon Italia 2025
EDA tools
tool correlation distribution missing version contributors
YData profiling table & heatmap * histogram bar & heatmap 4.16.1 116
dabl scatter plot histogram --- 0.3.2 25
klib table & heatmap ** line / histo bar & heatmap 1.3.1 6
PyGWalker calculated field drag & drop calculated field 0.4.9.15 23
** also single feature heatmap
* also interactions

42. PyCon Italia 2025
EDA tools
tool correlation distribution missing version contributors
YData profiling table & heatmap * histogram bar & heatmap 4.16.1 116
dabl scatter plot histogram --- 0.3.2 25
klib table & heatmap ** line / histo bar & heatmap 1.3.1 6
PyGWalker calculated field drag & drop calculated field 0.4.9.15 23
** also single feature heatmap
* also interactions

43. PyCon Italia 2025
EDA tools
tool correlation distribution missing version contributors
YData profiling table & heatmap * histogram bar & heatmap 4.16.1 116
dabl scatter plot histogram --- 0.3.2 25
klib table & heatmap ** line / histo bar & heatmap 1.3.1 6
PyGWalker calculated field drag & drop calculated field 0.4.9.15 23
** also single feature heatmap
* also interactions

44. PyCon Italia 2025
EDA tools
tool correlation distribution missing
YData profiling table & heatmap * histogram bar & heatmap
dabl scatter plot histogram ---
klib table & heatmap ** line / histo bar & heatmap
PyGWalker calculated field drag & drop calculated field
** also single feature heatmap
* also interactions

45. PyCon Italia 2025
EDA tools
tool correlation distribution missing year of birth contributors
YData profiling table & heatmap * histogram bar & heatmap 2016 116
dabl scatter plot histogram --- 2019 25
klib table & heatmap ** line / histo bar & heatmap 2020 6
PyGWalker calculated field drag & drop calculated field 2023 23
** also single feature heatmap
* also interactions

46. PyCon Italia 2025
EDA tools
tool correlation distribution missing year of birth contributors
YData profiling table & heatmap * histogram bar & heatmap 2016 116
dabl scatter plot histogram --- 2019 25
klib table & heatmap ** line / histo bar & heatmap 2020 6
PyGWalker calculated field drag & drop calculated field 2023 23
** also single feature heatmap
* also interactions

47. PyCon Italia 2025
EDA tools
tool correlation distribution missing year of birth contributors
YData profiling table & heatmap * histogram bar & heatmap 2016 116
dabl scatter plot histogram --- 2019 25
klib table & heatmap ** line / histo bar & heatmap 2020 6
PyGWalker calculated field drag & drop calculated field 2023 23
** also single feature heatmap
* also interactions

48. PyCon Italia 2025
EDA tools
tool correlation distribution missing year of birth contributors
YData profiling table & heatmap * histogram bar & heatmap 2016 116
dabl scatter plot histogram --- 2019 25
klib table & heatmap ** line / histo bar & heatmap 2020 6
PyGWalker calculated field drag & drop calculated field 2023 23
** also single feature heatmap
* also interactions

49. PyCon Italia 2025
Where we need to visualize the data ?
Data ingestion
● frequency
● quantity
● data type

50. PyCon Italia 2025
Where we need to visualize the data ?
Data ingestion
● frequency
● quantity
● data type
● monitoring

51. PyCon Italia 2025
Which graphs to use
for monitoring ?

52. PyCon Italia 2025
PMM - as an example

53. PyCon Italia 2025
PMM - as an example
graph color texture time tooltip
scatter plot mono or multi
per item
2d
value
line chart mono or multi 2d
status map per status now
bar chart multi 2d
texture mono or per status now ---
timeline chart per status 2d last value
heatmap gradient --- 2d bar chart
last value

54. PyCon Italia 2025
PMM - as an example
graph color texture time tooltip
scatter plot mono or multi
per item
2d
value
line chart mono or multi 2d
status map per status now
bar chart multi 2d
texture mono or per status now ---
timeline chart per status 2d last value
heatmap gradient --- 2d bar chart
last value

55. PyCon Italia 2025
PMM - as an example
graph color texture time tooltip
scatter plot mono or multi
per item
2d
value
line chart mono or multi 2d
status map per status now
bar chart multi 2d
texture mono or per status now ---
timeline chart per status 2d last value
heatmap gradient --- 2d bar chart
last value

56. PyCon Italia 2025
PMM - as an example
graph color texture time tooltip
scatter plot mono or multi
per item
2d
value
line chart mono or multi 2d
status map per status now
bar chart multi 2d
texture mono or per status now ---
timeline chart per status 2d last value
heatmap gradient --- 2d bar chart
last value

57. PyCon Italia 2025
PMM - as an example
graph color texture time tooltip
scatter plot mono or multi
per item
2d
value
line chart mono or multi 2d
status map per status now
bar chart multi 2d
texture mono or per status now ---
timeline chart per status 2d last value
heatmap gradient --- 2d bar chart
last value

58. PyCon Italia 2025
PMM - as an example
graph color texture time tooltip
scatter plot mono or multi
per item
2d
value
line chart mono or multi 2d
status map per status now
bar chart multi 2d
texture mono or per status now ---
timeline chart per status 2d last value
heatmap gradient --- 2d bar chart
last value

59. PyCon Italia 2025
PMM - as an example
graph color texture time tooltip
scatter plot mono or multi
per item
2d
value
line chart mono or multi 2d
status map per status now
bar chart multi 2d
texture mono or per status now ---
timeline chart per status 2d last value
heatmap gradient --- 2d bar chart
last value

60. PyCon Italia 2025
PMM - as an example
graph color texture time tooltip
scatter plot mono or multi
per item
2d
value
line chart mono or multi 2d
status map per status now
bar chart multi 2d
texture mono or per status now ---
timeline chart per status 2d last value
heatmap gradient --- 2d bar chart
last value

61. PyCon Italia 2025
PMM - as an example
graph color texture time tooltip
scatter plot mono or multi
per item
2d
value
line chart mono or multi 2d
status map per status now
bar chart multi 2d
texture mono or per status now ---
timeline chart per status 2d last value
heatmap gradient --- 2d bar chart
last value

62. PyCon Italia 2025
PMM - as an example
graph color texture time tooltip
scatter plot mono or multi
per item
2d
value
line chart mono or multi 2d
status map per status now
bar chart multi 2d
texture mono or per status now ---
timeline chart per status 2d last value
heatmap gradient --- 2d bar chart
last value

63. PyCon Italia 2025
PMM - as an example
graph color texture time tooltip
scatter plot mono or multi
per item
2d
value
line chart mono or multi 2d
status map per status now
bar chart multi 2d
texture mono or per status now ---
timeline chart per status 2d last value
heatmap gradient --- 2d bar chart
last value

64. PyCon Italia 2025
PMM - as an example
graph color texture time tooltip
scatter plot mono or multi
per item
2d
value
line chart mono or multi 2d
status map per status now
bar chart multi 2d
texture mono or per status now ---
timeline chart per status 2d last value
heatmap gradient --- 2d bar chart
last value

65. PyCon Italia 2025
PMM - as an example
graph color texture time tooltip
scatter plot mono or multi
per item
2d
value
line chart mono or multi 2d
status map per status now
bar chart multi 2d
texture mono or per status now ---
timeline chart per status 2d last value
heatmap gradient --- 2d bar chart
last value
https://pilestone.com/pages/color-blindness-simulator

66. PyCon Italia 2025
PMM - as an example
graph color texture time tooltip
scatter plot mono or multi
per item
2d
value
line chart mono or multi 2d
status map per status now
bar chart multi 2d
texture mono or per status now ---
timeline chart per status 2d last value
heatmap gradient --- 2d bar chart
last value

67. PyCon Italia 2025
PMM - as an example
graph color texture time tooltip
scatter plot mono or multi
per item
2d
value
line chart mono or multi 2d
status map per status now
bar chart multi 2d
texture mono or per status now ---
timeline chart per status 2d last value
heatmap gradient --- 2d bar chart
last value

68. PyCon Italia 2025
PMM - as an example
graph color texture time tooltip
scatter plot mono or multi
per item
2d
value
line chart mono or multi 2d
status map per status now
bar chart multi 2d
texture mono or per status now ---
timeline chart per status 2d last value
heatmap gradient --- 2d bar chart
last value

69. PyCon Italia 2025
PMM - as an example
graph color texture time tooltip
scatter plot mono or multi
per item
2d
value
line chart mono or multi 2d
status map per status now
bar chart multi 2d
texture mono or per status now ---
timeline chart per status 2d last value
heatmap gradient --- 2d bar chart
last value

70. PyCon Italia 2025
PMM - as an example
graph color texture time tooltip
scatter plot mono or multi
per item
2d
value
line chart mono or multi 2d
status map per status now
bar chart multi 2d
texture mono or per status now ---
timeline chart per status 2d last value
heatmap gradient --- 2d bar chart
last value

71. PyCon Italia 2025
Where we need to visualize the data ?
Data ingestion
● frequency
● quantity
● data type
● monitoring

72. PyCon Italia 2025
Where we need to visualize the data ?

73. PyCon Italia 2025
Where we need to visualize the data ?
Data transformation
● pyjanitor
● cleanlab
● dabl

74. PyCon Italia 2025

75. PyCon Italia 2025
Where we need to visualize the data ?

76. PyCon Italia 2025
Recap: ranking of the human perception
1. position, common scale
2. position, non-aligned
3. size, length
4. orientation, angle
5. size, area
6. size, volume & brightness
7. color
http://euclid.psych.yorku.ca/www/psy6135/papers/ClevelandMcGill1984.pdf
➢ scatter plot, point map
➢ scatter plot matrix
➢ bar chart, histogram
➢ pie chart, gradient lines
➢ tree map, bubble chart
➢ 3d, heat map
➢ color hue scales

77. PyCon Italia 2025
Recap: data-ink ratio (chapter 4)

78. PyCon Italia 2025
Recap: data-ink ratio (chapter 4)

79. PyCon Italia 2025
Recap: color blindness
All libraries
color palette: viridis

80. PyCon Italia 2025
Recap: color blindness
https://colorbrewer2.org/
All libraries
color palette: viridis

81. PyCon Italia 2025
Which graph tools to use ?

82. PyCon Italia 2025
Graph tools
tool code customization year of birth contributors
matplotlib (py) a lot max 2008 1531
bokeh (py) 2013 616
plotly.py (& js) 2013 254
marimo (py) 2023 139
pluto.jl (jl) 2020 122
datalore (SQL) JetBrains
hex (py & SQL) no code min Hex Technologies

83. PyCon Italia 2025
Graph tools
tool code customization year of birth contributors
matplotlib (py) a lot max 2008 1531
bokeh (py & js) 2013 616
plotly.py (& js) 2013 254
marimo (py) 2023 139
pluto.jl (jl) 2020 122
datalore (SQL) JetBrains
hex (py & SQL) no code min Hex Technologies
interact

84. PyCon Italia 2025
Graph tools
tool code customization year of birth contributors
matplotlib (py) a lot max 2008 1531
bokeh (py & js) 2013 616
plotly.py (& js) 2013 254
marimo (py) 2023 139
pluto.jl (jl) 2020 122
datalore (SQL) JetBrains
hex (py & SQL) no code min Hex Technologies
interact
notebook

85. PyCon Italia 2025
Graph tools
tool code customization year of birth contributors
matplotlib (py) a lot max 2008 1531
bokeh (py & js) 2013 616
plotly.py (& js) 2013 254
marimo (py) 2023 139
pluto.jl (jl) 2020 122
datalore (SQL) JetBrains
hex (py & SQL) no code min Hex Technologies
interact
notebook
cloud

86. PyCon Italia 2025
Graph tools
tool code customization year of birth contributors
matplotlib (py) a lot max 2008 1531
bokeh (py & js) 2013 616
plotly.py (& js) 2013 254
marimo (py) 2023 139
pluto.jl (jl) 2020 122
datalore (SQL) JetBrains
hex (py & SQL) low code min Hex Technologies
interact
notebook
cloud

87. PyCon Italia 2025
Graph tools
tool code bubble chart line chart double axis
matplotlib (py) a lot 6 6 10
bokeh (py & js) 16 10 29
plotly.py (& js) 12 9 40
marimo (py)
pluto.jl (jl)
datalore (SQL)
hex (py & SQL) low code
interact
notebook
cloud

88. PyCon Italia 2025
Graph tools
tool code bubble chart line chart double axis
matplotlib (py) a lot 6 6 10
bokeh (py & js) 16 10 29
plotly.py (& js) 12 9 40
marimo (py)
pluto.jl (jl)
datalore (SQL)
hex (py & SQL) low code
interact
notebook
cloud

89. PyCon Italia 2025
Graph tools
tool code customization year of birth contributors
matplotlib (py) a lot max 2008 1531
bokeh (py & js)
?
2013 616
plotly.py (& js) 2013 254
marimo (py) 2023 139
pluto.jl (jl) 2020 122
datalore (SQL) JetBrains
hex (py & SQL) low code min Hex Technologies
interact
notebook
cloud

90. PyCon Italia 2025
Graph tools
tool code customization year of birth contributors
matplotlib (py) a lot max 2008 1531
bokeh (py & js)
?
2013 616
plotly.py (& js) 2013 254
marimo (py) 2023 139
pluto.jl (jl) 2020 122
datalore (SQL) JetBrains
hex (py & SQL) low code min Hex Technologies
interact
notebook
cloud

91. PyCon Italia 2025
Graph tools
tool code customization year of birth contributors
matplotlib (py) a lot max 2008 1531
bokeh (py & js)
?
2013 616
plotly.py (& js) 2013 254
marimo (py) 2023 139
pluto.jl (jl) 2020 122
datalore (SQL) JetBrains
hex (py & SQL) low code min Hex Technologies
interact
notebook
cloud

92. PyCon Italia 2025
Thanks
for listening!
#PyConIT2025
alessandra.bilardi@corley.it
bilardi