Spider or Radar chart is named so because of their shape. This chart looks like a spider-web, on which data is arranged to form different shapes. This type of chart is used for representing multidimensional data, in a two-dimensional chart. It allows us to learn the features of two or more variables and discover if they are related or not. The data variables can range up to six to eight if they exceed that the chart becomes difficult to read. Each variable in the chart has its own axis, that starts at the center. The axes are also called spoke. The value is plotted along the same and joined together to form a polygon. All the axes are arranged at equal distance from each other.
Radar charts are best for determining which variable in a data is doing better than the rest. Hence, they are mostly used for performance analysis. These charts are also known by various other names such as web charts, star charts, and polar charts. Radar charts are preferred over column charts when dealing with a large set of data.
This chart can be used to compare the properties of a single component or compare the properties of two or more variables together. To explain this further, let us take an example of two beer samples.
Image Source: fusioncharts
In the above-given figure, a single brand of beer is analyzed for its features. Every axis is assigned a feature and the data relating to the brand are marked on the same. The points are joined with lines and the resultant polygon gives you the complete analysis of what components are present in your beer sample. Now, let’s compare two beer samples in one chart, using the same eight parameters.
Image Source: Radar Charts
Both the samples are given separate colors, so as to make it easier to distinguish between its factors. From looking at the chart, one can easily decide which sample would they prefer more.
Recommended reading: Why Do We Need Comparison Charts
Spider charts due to their distinctive quality are preferred when there’s a need to make a decision. It can help compare one’s performance to that of a group. For example, if you want to look at the performance of three students in their classes in high school, it can be easily depicted in a spider and radar chart.
Image Source: Spider Charts
Spider and radar charts are also seen used by the human resource department to check different employee groups and analyze their performance. A chart plotting the same is illustrated below.
Image Source: Chart Primers Radar Chart
It can also be used for product comparison, say for two mobile phones. A chart can be drawn listing out the performance of these mobile phones. Below is a graph where their features are graphically plotted. This makes it easier to understand which one comes with the most desirable feature and is apt as per your requirement.
Image Source: Radar Charts
Pros of using a Spider and Radar Chart
- Spider and radar charts are best to use when making a decision by comparing different features of a data.
- More than one variable or sample’s features can be compared using this chart.
- These charts take us less space in comparison to most charts.
- The shape and size of the polygon formed by the values provide a clear summary of all the values plotted.
- Concentric circles inside the chart can be used as grid lines for measurement.
- Different colors or patterns are used for each polygon, which makes it easier to identify and distinguish between them.
- Radar and spider charts are good at showing variation and common characteristics in data.
- These charts are visually aesthetic and look presentable.
Also read: Scatter Charts: Why And When To Use It
Cons of using a Spider and Radar Chart
- Difficulty can arise when comparing different quantities of values on a different axis, as they might have varying measuring scale.
- Comparing values across a circle is harder than comparing them on a straight line.
- Area of the polygon varies with variation in the arrangement of axes.
- Radar charts are harder to plot compared to other charts.
- These charts are limited to certain types of data.
- It is best not to attempt to plot more than 3 sets of a group in a radar chart.
- Too many polygons can make the chart messy and confusing to read.
- When too many variables or feature are there, too many axes are present. This crowds up the chart and makes it unreadable.
- In this type of chart, one polygon might cover up another and hide some of the data available.
- It is difficult to compare the size of the axis visually, as radial lengths may vary.
- These charts cannot compare values in a single axis, using a single variable.