If you have encountered the terms 'polygon chart', 'radar chart', 'spider chart', 'web chart', 'star plot', and 'cobweb chart', you may be wondering whether they refer to different chart types or are simply different names for the same thing. The short answer is that they all describe the same fundamental visualization — a chart that displays multivariate data on axes radiating from a central point, with data points connected to form a closed polygon.

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The Names Explained

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The term 'radar chart' originates from the visual resemblance to a radar display — data radiates outward from a center point like signals from a radar station. 'Spider chart' refers to the web-like grid of lines connecting the axes, which resembles a spider's web. 'Polygon chart' describes the geometric shape formed by connecting the data points — a polygon. 'Star plot' and 'star chart' emphasize the starburst pattern when many axes are used. 'Kiviat diagram' is a more formal academic term named after Ben Shneiderman's graduate student Phil Kiviat, who popularized the visualization in software metrics research in the 1970s.

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All these names — radar chart, spider chart, polygon chart, star plot — describe the same visualization technique.

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Technical Differences Within the Family

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While the names are largely interchangeable, there are a few technical distinctions worth noting. Some chart libraries distinguish between a 'radar chart' (which uses a circular grid) and a 'polygon chart' (which uses an angular polygon grid). In AnyChart's documentation, for example, a 'polygon chart' specifically refers to an area series on a polar plot with a categorized X-scale. In Highcharts, the 'polygon series' is a data series that draws a polygon connecting data points on a scatter chart. These library-specific definitions differ from the general usage of the term in data visualization.

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Polygon Chart vs Bar Chart

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The key difference between a polygon chart and a bar chart is the number of variables each handles most effectively. Bar charts are excellent for comparing a single variable across many categories — for example, sales revenue by month. Polygon charts are designed for comparing multiple variables for a single entity or comparing multiple entities across a fixed set of variables. If your data has more than two dimensions and you want to see the overall profile rather than individual comparisons, a polygon chart is usually the better choice.

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Polygon Chart vs Parallel Coordinates

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Both polygon charts and parallel coordinates plots display multivariate data. The difference is in layout: polygon charts arrange axes radially (in a circle), while parallel coordinates arrange axes vertically in a row. Polygon charts are more compact and easier to read for a small number of entities being compared. Parallel coordinates handle larger datasets better because the axes can be extended to accommodate more data points without the chart becoming cluttered.

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When to Use Each Chart Type

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Use a polygon/radar/spider chart when you want to show the performance profile of one or a few entities across multiple variables, especially when the goal is to identify overall strengths and weaknesses visually. Use a bar chart when you want to compare a specific metric across many categories. Use a parallel coordinates plot when you have a large dataset with many entities and need to show the full distribution of each variable while tracking individual trends. Use a scatter plot or bubble chart when you are primarily interested in the relationship or correlation between two or three variables.

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