We have all heard about charts, even used some, but how well do we really know about them? Let’s start with what charts mean. Charts also called maps or graphs are an excellent way to communicate information in graphical format. There are many types of charts available to convey your data, the idea lies in choosing the best one that suits one’s needs.
A chart should be chosen in such a way that it allows the user to grasp the information conveyed via it in a simple and easier way than looking at just a table of data. It is often used to represent a large amount of data or parts of data.
The term chart has multiple meanings when it comes to data presentation. Consider a data chart, which is a diagram or a graph which conveys the numerical and qualitative data. Then come maps, which are too; a kind of chart and gives out a wide set of information. Examples are aeronautical maps, nautical maps, etc. There are other specific constructs that fall under the category of charts, such as a music chart or a record chart.
Types of Charts
Although there are many types of charts out there, the most common names you will come across are histogram, pie charts, bar charts, column charts, line charts, doughnut charts, area charts, scatter charts, spider charts, radar charts, gauge charts, and comparison charts. To choose the most suitable one, you should consider the total data points, data variables, and time period of your data. Each chart has its own advantages and should be used wisely to highlight the same with the desired data you want to represent.
1. Line charts
Line charts or line graphs are the most basic graph type used in many fields. It is used to display the information in data points, i.e. small marks. These marks or points are known as markers, connected by straight lines. Thus, forming a line, that shows the change in data. Other than comparing two parameters, it compares the data over the same period for different groups.
The horizontal axis usually represents the numerical data, for example, time. While the vertical axis represents other related data that is to be observed over time. A line chart is also used to conceptualize a trend, that is a change in a factor over time. This line formed is drawn chronologically and in this case, the line charts are called run charts.
An easy example of a line chart will be plotting a given table of data of speed versus time.
When I say Bar charts, lots of high and low bars arranged in a line might pop in your head. Well, that’s exactly what bar charts are. To be specific about its usage, bar charts are used for comparing different types of data by different groups.
A bar chart or a bar graph displays your categorical data in rectangular bars with heights and lengths proportional to the values they represent. They are mostly used for comparing concepts or percentages of a given set of data. Compared to other charts bar charts are preferred when dealing with larger data and numbers. There are different types of bar charts mainly, horizontal bar charts, stacked bar charts and grouped bar charts.
Bar charts are usually drawn vertically and that is why is commonly called vertical bar chart. But it is possible to draw a bar chart horizontally. This is, the longer the bar, the larger the category. This graph or chart comes in handy when there is a large number of different categories and there is not enough space to fit all the columns required for a vertical bar chart.
Group bar charts are used to display information about different sub-groups. Each rectangular block is colored or shaded differently to distinguish between them, keeping in mind that too much information is not added making it complex to the viewers to comprehend.
Group bar charts can be drawn as a horizontal or vertical chart, based on the data that needs to be implemented. Stacked bar charts, on the other hand, are very similar to group bar charts, however, they’re used to display the sub-groups that fall under different categories. Here, the bars representing the sub-groups are placed on top of each other to make a single column, or side by side to make a single bar. Different colors or patterns are used to differentiate between the sub-groups.
Example of a simple bar chart is plotted below, human loss in the world war for different countries.
If you google the definition of a histogram it will say, “a diagram consisting of rectangles whose areas are proportional to the frequency of variable”. If that didn’t answer your question, let me break it down a little for you. A histogram is a visual combination of the line chart and a vertical bar chart. It provides an accurate representation of the distribution of numerical data by organizing a group of data into user-specified ranges.
Histograms are very similar looking to bar charts, the only difference being that they are only used to plot the frequency of variable occurrences in continuous data divided into classes called bins. The continuous variable is plotted in the x-axis and is broken down into separate intervals and the number of values you have in that those intervals determines the height of the bar. Histograms are a good way of illustrating distributions of data. Here’s an example of a bar chart, showing the distribution of age groups.
Pie charts have always been an easy way to understand information. It is the most fun chart to convey your ideas. These charts break the whole data into parts and make it easier to grasp. This chart is in the shape of a pie and shows the relationship between the main and sub-categories of your data. It is mainly used when dealing with a categorized group of data and to differentiate data based on a single variable. Before drawing a pie chart, one must ensure the size of each part and that all the pieces add up to as one.
There are also sub-types of pie chart available namely, 3-D pie chart and exploded pie. A 3-D pie chart also called a perspective pie chart gives a 3D outlook to a normal pie chart. These charts are no improvement to the usual pie charts and are used mostly because of their visually aesthetic appearance. Because of a third-dimension inclusion, these are also a bit hard to understand in one look. An exploded pie chart is formed when the slices of a pie chart are moved further away for further significance. They look like the pieces of a pie cut out are all moved slightly outward from its center.
An example of a pie chart showing the monthly sales analysis is illustrated below.
These are the charts that look like an ocean of lines in the form of a graph. Area charts are like line charts, the difference being that the area between the x-axis and line is filled with color or pattern. It helps display part to whole relations, that is, in parts, it gives you the whole change in the data. With area charts, one can analyze individual as well as an overall change in data and information.
There are 2 types of area charts, stacked area charts, and 100% stacked area charts. Each of these charts is available in 2-D and in 3-D format with X, Y, and Z axes respectively. Both these charts are effective in showing the nature of your selected data type. Below is an example of an area chart analyzing two series.
This chart as the name suggests is a scatter diagram. A scatter chart is used to show the relationship between two different variables. They are drawn using, straight lines, markers, and points. The main purpose of using a scatter chart is to illustrate the values of two series or variables and compare them over time or any other parameter. It provides you with the degree of difference between two variables, which is known as correlation.
If the plotted graph forms a band from lower left to upper right there is a positive correlation between the variables. If it goes the other way around, that is, goes from upper left to lower right, that shows a negative correlation. If the pattern formed is hardly visible, that indicates that no correlation exists between the variables. An example of the scatter chart shows means data increase is shown below.
The chart is called a doughnut chart as it is drawn in the shape of a doughnut. Data that can be arranged in rows and columns in a worksheet are the only ones that can be plotted in a doughnut chart. Doughnut charts are very similar to pie charts and show the relationship between the parts and the whole, only here more than one series can be plotted in. The more the number of series is, the more rings are added into the doughnut chart.
Doughnut charts have a number of elements, including a division of segments. One can add labels and text boxes to point out what each ring in the doughnut denotes. Once a doughnut chart is created, the slices of the chart can be rotated in different perspectives and each slice can be analyzed separately as a single specimen and modified accordingly, in turn bringing further modifications to the chart. An example of a doughnut chart is illustrated below.
Spider and Radar Charts
The outlook of this chart is that of a spider web, with data plotted on it. These charts are also known from various other names such as web charts, star charts, and polar charts. Spider and radar charts are preferred over column charts to plot a large set of different data groups as can be used to show 2D diagrams of at least 3 variables on axes, making it more reliable.
Spider and radar charts are mainly used by the human resource department to check different employee groups and analyze their performance. It can also be used for product comparison, says listing out the performance of two mobile phones. Their features are graphically plotted in the graph and it becomes easier to understand which one comes with the most desirable feature. The example of the same is pictorially illustrated below.
Gauge charts make use of a pointer or a needle to show data as a reading on a dial. It looks like meter with an indicator pointing out the reading. They show an individual factor and are ideal for showing KPIs, that is, Key Performance Indicators. They are suitable charts for business departments and are commonly used by employers and managers for project analysis.
The main advantage of gauge charts is its representation of a value and meaning of individual measurement. However, it holds a limitation that it cannot show more than one variable detail at a time. A gauge chart can be created in excel, combing a doughnut chart and a pie chart in a single chart. An example of the same is illustrated below.
Comparison charts are used to draw comparisons between different fields based on different parameters. These charts are called cluster diagrams and are used to compare objects, units, and groups of data. They provide us with visual data both quantitative and qualitative wise. Comparison charts can be used to draw comparisons based on many factors like items, components, distribution frequency, reliability, power, correlation, etc.
Comparison charts are used by organizations to analyze the progress of different data groups. It can be used in various other fields too, to check which of two or more variables are the prominent one. That is why it remains an important aspect in business and science fields. An example of a comparison chart is illustrated below.
This was all about charts, what we use them for and what are the types of charts available. Hope this article helped you in learning more interesting facts about charts and choosing the right one as per the requirements of your data.