12 Most Common Types of Charts in Data Visualisation
In the current era of large amounts of information in the form of numbers available everywhere, it is a difficult task to understand and get insights from these dense piles of data.
Data visualisation is the way which helps us in understanding what data tells us. It is more meaningful and appropriate when we use suitable charts to visualise data and get insights from it.
In this article, we will go through the common chart types and get to know about their applications scenarios. So by this, we can use appropriate chart types that will be helpful in getting characteristics of the data. To get an introduction about data visualisation in detail you can refer to the article- What and Why of Data Visualisation?
Now, let us see the different chart types one by one.
1. Line Chart
Line chart or graph is used to illustrate trends in data over a time span or continuous time interval. The line chart tends to reflect different things as they change over time by connecting different plotted points.
Multiple trends can also be displayed by plotting lines of different colours. It is advisable not to exceed 5 lines on the same graph for the clarity.
For e.g. the scenarios where we can use the line chart are monthly rainfall, annual sales of a company, month over month trends of stock prices, portal users, etc.
2. Column Chart
Column charts are the most basic charts which use columns to show the numerical values between categories. A column chart includes data labels along the horizontal axis with metrics or values along the vertical axis. It takes advantage of the height of the column to tell the difference in the values and the human eye is quite sensitive to the difference in heights.
Column charts can also be used for the comparison between different types of categories. Clustered and Stacked column charts can be used for it.
Some of the scenarios where column charts can be used are — sales by different region, product category, comparison of classified data.
3. Bar Chart
Bar charts are similar in use as column charts only the positions of its two axes are changes. Bar charts are generally used when there are a relatively large number of categories or they can be useful while displaying negative values.
Bar charts can also be stacked or clustered while comparing different types of categories. The scenarios where bar charts are used are the same as column charts.
4. Pie Chart
Pie charts are used to represent the proportions of different classifications in various fields. They are very useful in knowing how much portion of something is of a whole. But we should limit the numbers of classifications as the number of slices increases the chart become unhandy and we are not able to recognise the proportion of each slice as size distinction is not obvious.
There is a multi-layer pie chart also, which shows the proportion of different categorical data and also reflects the hierarchical relationships through it.
The scenarios in which pie charts can be used are such as the comparison between population segments, budget allocations, the male-female ratio, online traffic sources, etc.
5. Area Chart
Area chart represents the change in data(quantities) over time same as of the line chart. It is formed on the basis of the line chart in which the are between the trend-line and axis is filled with colour. As filling with colours better highlights the trend information.
The fill should be somewhat transparent or different so that the user can easily observe the overlapping relationship between different trends. Area charts can be used to depict time-series relationship, part-to-whole analysis, a simple comparison between the trend of each category, etc.
6. Scatter Chart
Scatter plot is used to identify two relationships between two measures(quantities). In this, the two variables are plotted in the form of points on the points on the rectangular coordinate system. The relationship we identify between two variables is a correlation.
Scatter plot is used mainly to identify how well we can infer the vertical values from the horizontal axis values. For scatter plot we need a lot of data otherwise we can’t assure that the identified relationship is obvious or not.
7. Bubble Chart
A bubble chart is the variant of the scatter plot. It is a multivariate chart that displays three-dimensional data. In the bubble chart, the x & y-axes are used to express two dimensions or measures and the size of the bubble determines the third value. The bubbles can be classified into different categories by using different colours.
Bubble charts are mainly used to compare and show the correlations between classified circles using positions and proportions.
8. Gauge Chart
Gauge Chart is used to display the progressive values. The scale represents a metric, in which the pointer angle represents the value of a dimension represented by the pointer.
The gauge can be in the form of a ring, half ring or a tube bar, indicating the progress. The scenarios where gauge can be used are for comparison between intervals, achieved value versus targeted value.
9. TreeMap
A TreeMap is used to represent the hierarchical structure of the data in a space-efficient way. The visualisation is created using the method of nested rectangles and displaying the quantities via area for each category. We can drill down within a treemap to an unlimited number of levels.
TreeMaps can be used when data needs to be studied with respect to two metric values, having a large amount of hierarchical data, to get a high-level view of similarities and differences within one category or between multiple categories.
10. Funnel Chart
A funnel chart is a type of area chart which helps in visualising the progressive reduction of data from one phase to another amounting 100 per cent in total. The size of the area is determined by the series of value as a percentage of the total of all values.
Funnel charts are suitable for comparing rankings. They can be used in visualising the sales conversion data, in analyzing data and managing order and sales cycles, evaluation of a particular process, and in standard value comparison.
11. Waterfall Chart
A waterfall chart is a modified type of column chart. A waterfall chart helps in understanding the cumulative effect on the initial value which is increased or decreased by a series of intermediate values leading to s final value.
In the waterfall chart, the first column usually represents the initial value to total value, the last column represents the total value and the intermediate columns appear to float, and represent the negative or positive changes from one period of time to another.
Waterfall charts are most widely used in the Finance sector to show net value transition, profit variation from the start of a year till the end, and it is also effective to use when to display gradual changes in the value measures over a period of time.
12. Map Chart
Map Charts are the visualisation which helps us to position our data in the geographical context to get the intuition about the regional distribution on the different levels such as world, countries, states, etc. We can show data on maps in different ways such as point map, flow map and heat map.
1. Point Map
A Point map uses the method of plotting points on a geographical layer or map. The distribution in the form of points makes it easy to grasp the overall distribution of data. We can also use bubbles instead of points which have different colours and sizes based on values and categories.
2. Flow Map
A Flow map allows the interaction between the outflow and inflow area. It is usually represented by the line connecting the geometric centres of the location. The direction of the line specifies the direction of flow. The width or colour of the line indicates the flow value. Flow Maps can be used to display the imports, exports, geographic migrations etc.
3. Heat Map
A Heat Map uses the colour gradients range from light to dark based on the different values which are completely in the specified region. Heat Map can be used in specifying the temperature distribution, population density, etc.
Conclusion
All of the above 12 charts are the most frequently used charts in data visualisation. You can create these visualisations on various tools like Power BI, Tableau, Microsoft Excel, etc. These are the basic charts but most of the complex charts are derived from these charts. However, as simple the chart is, the easy it is to understand and get the right insight from data. So, keep this in mind, and try to get a grip over these common charts.
