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Today, when we use charts to perform data visualization operations with ease, I don’t know if you have thought about a question:
Where did these graphs come from?
At first, people don't realize that the ability to use graphics to describe boring words, and to represent quantities through graphics, is a relatively new field of development.
The predecessors planted trees, and the descendants took advantage of the shade. This article will take you to understand the development history of those graphs/charts.
1. Line chart
In 1786 , William Playfair drew a line graph of England's import and export data from 1700 to 1780. It is considered to be the earliest line graph in history, that is, a line graph. The horizontal axis is the time scale, the year, and the vertical axis is the value.
(Insert a digression. 1786 corresponds to the Qianlong period of the Qing Dynasty in China. We always say that data analysis must have comparative thinking. Here comes the comparison.) A line
chart is a chart composed of a rectangular coordinate system, points and lines. It is usually used to show the change of numerical data over time. Compared with the bar chart, it can better reflect the data trend.
Attention should be paid to use:
- The vertical axis generally starts from 0
- Choose a relatively thick linetype
- Try not to have more than 5 lines.
- If it is a predicted value, please indicate it with a dotted line
2. Bar graph
Still this year, William Playfair creatively used bar charts to present the comparison of discrete quantities in "Illustrations of Commerce and Politics", describing Scotland's import and export data from 1780 to 1781, from his original manuscript below We can see that the abscissa represents the specific value of imports and exports, and the ordinate represents different countries, which is no different from the bar graph we use today.
Bar charts can be used to represent proportions , compare relative sizes, be more precise, and make it easier to find subtle differences. Bar charts can be vertical or horizontal. Horizontal bar charts are used to display category data, and vertical bar charts are used to display Numeric data.
Pay attention when using:
• Use the same color for the same series of data
• Try not to use slanted labels
• If you add data labels, delete the grid lines
• Arrange the data from large to small.
3. Pie chart
Playfair firmly believes that a picture is worth a thousand words, and he invented pie charts, line charts, etc. He has engaged in many occupations in his life, such as businessman, statistician, postman, translator, accountant, etc. It can be said that he is a proper slash youth, maybe It was these professional experiences that inspired him to create graphics.
Fifteen years after the invention of the bar chart, that is, in 1801 , Playfair used a pie chart to describe the proportion of the territory of the Turkish Empire in Asia, Europe and Africa in his "Statistical Abstracts" in 1801. From his It can be seen from the original manuscript that Europe accounts for 25% (upper right angle), Asia accounts for 60%, and Africa accounts for 15%. This is the first appearance of the pie chart.
(1801, when China entered the era of Emperor Jiaqing of the Qing Dynasty)
The pie chart is a circular statistical chart that divides the data into several sectors with obvious differences. In the pie chart, the arc length (as well as the central angle and area) of each sector indicates the proportion of the category to the whole, and these sectors together just form a complete circle.
Pie charts mainly reflect proportions . However, since human beings are not as sensitive to angles as lengths, when all sectors are of similar size, it does not make much sense to use pie charts. It is recommended to use histograms or bar charts instead.
As shown in the figure below, the nuances cannot be distinguished with a pie chart, but it is clear at a glance with a histogram.
Note when using:
- When using, it must be confirmed that the data of each sector add up to 100%;
- Avoid more than 5 sectors, and try to make the chart concise and clear;
- Pay attention to the arrangement order of the sectors. Under normal circumstances, place the largest sector at the 12 o'clock direction, and then arrange it in order according to the area;
- Finally, the correct use of color can distinguish the sectors that need to be emphasized without dazzling the eyes.
4. Scatter plot
In 1833 , John Herscherl published an article on the observation of binary star orbits, which used a scatter diagram to show the relationship between observation time and position angle. This is the first scatter diagram with modern significance. John Herscherl was the son of William Herscher, who discovered Uranus and infrared light.
(In 1833, during the Daoguang period of the Qing Dynasty, the first Opium War was about to break out)
The charts we mentioned above are all one-dimensional, and the scatter chart is a typical two-dimensional chart, which is composed of multiple coordinates composed of two sets of data Statistical charts of points are mainly used for displaying data trends and explaining correlations between data.
Note when using:
- Scatter plots are suitable for exploring the relationship between variables
- When using scatter plots for correlation analysis, if the amount of data is too small, there is not much explanatory significance
- Too large and too many data points will also affect the readability of the data graph
- Data classification should not be too much, too many classifications will lose the meaning of comparison
5. Nightingale's Rose
The Nightingale rose diagram is a variant of the pie chart, which was invented by Ms. Florence Nightingale, also known as the polar region diagram and the cockscomb diagram.
Speaking of Ms. Nightingale , she is also very legendary. She was a nurse first, a statistician second, and the first female member of the Royal Statistical Society.
In the 1850s, Britain, France, Turkey and Russia fought the Crimean War. Nightingale volunteered to serve as a field nurse. The sanitation conditions of the hospital at that time were extremely poor, even without clean water and toilets, and the mortality rate of the injured was as high as 42%. It was not until 1855 that the health committee came to the hospital to improve the overall sanitation environment, and the mortality rate dropped dramatically to 2.5%. . Nightingale at the time noticed this and believed that the government should improve the conditions of field hospitals to save more young lives.
Out of concern that the statistical results would not be taken seriously, she invented a colorful chart format to make the data more impressive.
This picture is the one used by Florence Nightingale to report the incident at that time, to express the seasonal death rate of the military hospital. From an overall point of view**: This picture is used to illustrate and compare the wounded patients in the field hospital due to different causes. The number of deaths from various causes, each sector represents the number of deaths in each month, and the larger the area, the greater the number of deaths. **
(In the 1850s, corresponding to the Xianfeng era of the Qing Dynasty, the first Opium War broke out at this time, China had become a semi-colonial and semi-feudal society, and the second Opium War broke out in 1856)
There are two rose diagrams in this picture, one large and one small. The larger rose diagram on the right shows the data from April 1854 to March 1855; the rose diagram on the left shows the data from April 1855. The data from March to March 1856, with April 1855 as the boundary, divides the 24-month data into two graphs on the left and right and connects them with black lines, because this is probably the time when the Sanitation Committee came to improve the environment date, and so we can compare the approximate proportions of deaths to their causes in the two years.
• Areas of gray are significantly larger than areas of other colors. This means that most casualties are not directly from the war, but from infections in poor medical settings.
• After the Sanitary Commissioners arrived (March 1855), the death toll dropped significantly.
Her method moved high-level people at the time, including the military and Queen Victoria herself, so the proposal for medical improvement was supported. Because the shape of the picture resembled a blooming rose, the "Nightingale Rose Picture" was also named From this.
Regarding the method of making this graphic, I have detailed instructions in the article " Teaching You to Make a Super Stunning Nightingale Rose Chart".
Note when using:
- The pie chart uses the size of the angle to reflect the value or proportion;
- The Nightingale Rose Diagram uses the radius of the fan to represent the size of the data, and the angles of each fan are consistent.
- It can be said that the Nightingale rose diagram is actually a polarized circular histogram. It exaggerates the visual effect of the difference between the data and is suitable for displaying data with small differences in the data
6. Snow's cholera map
Cholera is an acute diarrheal infectious disease caused by ingested food or water contaminated by Vibrio cholerae, which can cause diarrhea, dehydration and even death within hours.
When cholera broke out in Soho, London in 1854 , people didn't know what caused cholera, let alone how to deal with it. Faced with this infectious disease with a high infection rate and a high fatality rate, people at that time were helpless.
British anesthesiologist and epidemiologist John Snow visited the epidemic area, used scattered points on the map to represent the relationship between cholera cases and surrounding water pumps, and used statistical data to illustrate the correlation between water quality and cholera, and finally locked a public well.
(The Second Opium War broke out in 1856, and the Qing government was forced to sign a series of unequal treaties)
Although John Snow did not discover the pathogen of cholera, he creatively used spatial statistics to find the source of infection, which gave later Unlimited use value of people.
With the maturity of the public health system, combined with antibiotic treatment, cholera is no longer so terrible.
7. Sankey Diagram
In 1812, Napoleon declared war on Russia, marched from France to Moscow, and finally failed.
French civil engineer Charles Joseph Minard published a statistical graphic on November 20, 1869, which combined the Sankey diagram with cartography and temperature line charts to show the progress of the war very intuitively . How the army of 422,000 people paid a heavy price under the influence of battles, geography and freezing, and finally reduced to only 10,000 people. This is the famous Napoleon's Eastern Expedition map and the earliest Sankey map.
This diagram shows the size of Napoleon's army, distance traveled, latitude, longitude, direction of travel, location on a specific date or event.
(1869, during the Tongzhi period of the Qing Dynasty, Empress Dowager Cixi came to power)
A Sankey diagram is a schematic representation of a process, used to describe the flow from one set of values to another set of values. The width of the branch corresponds to the size of the data flow. As shown in the figure below, the process of user conversion is described, how many users add to the shopping cart, and how many users pay.
Note when using:
- Avoid too fancy colors that affect reading
- The Sankey diagram is characterized by energy conservation, so the width of each edge should remain constant
reference:
- http://www.tuzhidian.com/chart?id=5c553ca258461d3fa6136677
- https://blog.csdn.net/weixin_38754337/article/details/113532959
- "The Beauty of Statistics"
- http://finance.sina.com.cn/money/fund/fundzmt/2020-01-21/doc-iihnzahk5562348.shtml
- https://www.datavis.ca/papers/friendly-scat.pdf