Data visualization |

Target User / Analyst

A heat map is a data visualization type where the individual values contained in a matrix through variations in coloring. The term “Heat map” was originally introduced by software designer Cormac Kinney in 1991 to describe a 2D display depicting real time financial market information even though similar visualizations have existed for over a century.
Heat maps are useful for visualizing variance across multiple variables to display patterns in correlations
Fractal maps and tree maps both often use a similar system of color-coding to represent the values taken by a variable in a hierarchy. The term is also used to mean its thematic application as a choropleth map. 
Many also incorrectly refers to heat maps as Choropleth maps – properly because of the misleading term ‘map’. But a choropleth maps include different shading or patterns within geographic boundaries to show the proportion of a variable of interest, whereas the coloration a heat map does not correspond to geographic boundaries.

Heat Map

A dot plot or dot chart is a statistical chart consisting of data points plotted on a fairly simple scale, typically using filled in circles. There are two common versions of the dot chart. The first is described by Leland Wilkinson as a graph that has been used in hand-drawn (pre-computer era) graphs to depict distributions. The other version is described by William Cleveland as an alternative to the bar chart, in which dots are used to depict the quantitative values (e.g. counts) associated with categorical variables.

Dot Plot

A histogram is a chart that groups numeric data into bins, displaying the bins as segmented columns. They’re used to depict the distribution of a dataset: how often values fall into ranges. The histogram was first introduced by Karl Pearson.
To construct a histogram, the first step is to bin the range of values, and then count how many values fall into each interval. A rectangle is drawn with height proportional to the count and width equal to the bin size, so that rectangles abut each other.


A sparkline is a small intense, simple, word-sized graphic with typographic resolution. Sparklines mean that graphics are no longer cartoonish special occasions with captions and boxes, but rather sparkline graphics can be everywhere a word or number can be: embedded in a sentence, table, headline, map, spreadsheet, graphic. Data graphics should have the resolution of typography. (Edward Tufte, Beautiful Evidence, 46-63.)


A violin plot is a method of plotting numeric data. It is a box plot with a rotated kernel density plot on each side. The violin plot is similar to box plots, except that they also show the probability density of the data at different values. Typically violin plots will include a marker for the median of the data and a box indicating the interquartile range, as in standard box plots.

Violin Plot

Comparing the distribution of data with a theoretical distribution from an ordinary histogram can be difficult because small frequencies are dominated by the larger frequencies and it is hard to perceive the pattern of differences between the histogram bars and the curve. Therefore John Tukey introduced the Hanging Rootogram in 1971 (also called Tukey’s Hanging Rootogram) in order to solve these problems. In this visualization the comparison is made easier by ‘hanging’ the observed results from the theoretical curve, so that the discrepancies are seen by comparison with the horizontal axis rather than a sloping curve. As in the rootogram, the vertical axis is scaled to the square-root of the frequencies so as to draw attention to discrepancies in the tails of the distribution.
It is a variation of the concept of histograms and Pareto charts by combining observed and predicted in a simple way where the line charts display that the data is continuously changing.

Hanging Rootogram

A bubble chart is a type of chart that displays three dimensions of data. Each entity with its triplet (v1, v2, v3) of associated data is plotted as a disk that expresses two of the vi values through the disk’s xy location and the third through its size. Bubble charts can facilitate the understanding of social, economical, medical, and other scientific relationships. Bubble charts can be considered a variation of the scatter plot, in which the data points are replaced with bubbles.

Bubble Chart

A Gantt chart is a type of bar chart, that visualises various categories into time series. Gantt charts illustrate the start and finish time in time period blocks. 
A Gantt chart is often used in project management as one of the most popular and useful ways of showing activities (tasks or events) displayed against time. On the left of the chart is a list of the activities and along the top is a suitable time scale. Each activity is represented by a bar; the position and length of the bar reflects the start date, duration and end date of the activity.
It is similar to the Column Range with the difference of indicating time.

Gantt Chart

Stacked Area Chart is similar to the simple Area Chart, but here is uses multiple data series that start each point from the point left by the previous series. It is useful for comparing multiple variables changing over interval.

Stacked Area Chart

In descriptive statistics, a boxplot is a convenient way of graphically depicting groups of numerical data through their quartiles. A box plot displays median, higher/lower quartiles and maximum/minimum.  Outliers may be plotted as individual points. The spacings between the different parts of the box indicate the degree of dispersion (spread) and skewness in the data, and show outliers. Box plots can be drawn either horizontally or vertically.
The violin plot is similar to boxplots, except that they also show the probability density of the data at different values.


A waterfall chart helps in understanding the cumulative effect of sequentially introduced positive or negative values. The waterfall chart is also known as a flying bricks chart or Mario chart due to the apparent suspension of columns (bricks) in mid-air. Normally used for understanding how an initial value is affected by a series of intermediate positive or negative values.
Not to be confused with the likely named Waterfall Plot.

Waterfall Chart

A trendline is a line that is drawn over pivot highs or under pivot lows to show the general course or tendency of something. Trendlines are a visual representation of support and resistance in any time frame.


The multi-level pie chart is a special type of chart that allows you to show symmetrical/asymmetrical tree structures in a consolidated pie-like structure.
Though similar, the multilevel piechart should not be confused with the multi-level donut chart, as it contains no connected hierarchy and tree structure, but only displays independant donut rings for comparison.

Multi-level Pie Chart

Connection Map is used to display network combined with geographical data. It can be used for visualising flight connections, flow of import/export or migration, any kind of connections between different locations. By combining thickness, colour, or pattern to the lines or adding another type of visualisation (for example, bar chart or dot plot), you can add numeric values to Connection Map. It is related to a Flow Map but display no quantitative values between the connections.

Connection Map

A Pie Chart Map is simply a combination of a Pie Chart data visualization and a map. It is used to visualize location and numerical proportion in a simple way. Sometimes you will see a combination of both Pie Chart, Map and Bubble Chart. Where the size of the Pie Chart circle allows one more dimension to the visualization.

Pie Chart Map

Treemaps display hierarchical (tree-structured) data as a set of nested rectangles. Each branch of the tree is given a rectangle, which is then tiled with smaller rectangles representing sub-branches. A leaf node’s rectangle has an area proportional to a specified dimension on the data. Often the leaf nodes are colored to show a separate dimension of the data.


A dot density map is a map type that uses a dot or another symbol to show the presence of a feature or phenomenon.
In a dot density map, areas with many dots indicate high concentrations of values for the chosen field and fewer dots indicate lower concentrations.
Each dot on a dot-density map can either represent one single recording of a phenomenon (one-to-one) or represent a given quantity of it (one-to-many).

Dot Density Map

It can be helpful to plot multiple datasets using a 3D form of bar chart or histogram. The multiple series 3D bar charts can be used for data sets with 3 variables (x,y, z)
Often the clarity of presentation can be reduced if the presentation is too crowded.

Multiple Series 3D Bar Charts

Cartograms distort the shape of geographic regions so that the area directly encodes a data variable. A common example is to redraw every country in the world sizing it proportionally to population or GDP. Can be done by circles, squares or distorted maps by manipulating the initial map.
Primarily used to visualize data related to countries, regions or states, for example votes in elections, population or income.


Stacked ordered area chart is geared towards showing rank change. Use it instead of a stacked area chart when you want to show the change of order over time. The inner categories are connected by ribbons across the columns to help you visually see how the rank changes across the columns.
A similar visualization type is the sorted stream graph

Stacked Ordered Area Chart

A Bubble timeline is a way to display a set of events or items on a timeline with a variable displayed as the the are size of the bubbles. In essence the bubble timeline is a compound data visualization, of a scaled timeline and a proportional area chart.

Bubble Timeline

Parallel coordinates is a common way of visualizing high-dimensional geometry and analyzing multivariate data. This visualization is closely related to time series visualization, except that it is applied to data where the axes do not correspond to points in time, and therefore do not have a natural order. Therefore, different axis arrangements may be of interest.

Parallel Coordinates

A population pyramid, also called an age pyramid or age picture diagram, is a graphical illustration that shows the distribution of various age groups in a population, which forms the shape of a pyramid when the population is growing. It is also used in ecology to determine the overall age distribution of a population; an indication of the reproductive capabilities and likelihood of the continuation of a species.

Population Pyramid

A scatter plot is a type of mathematical diagram using Cartesian coordinates to display values for two variables for a set of data. The data is displayed as a collection of points, each having the value of one variable determining the position on the horizontal axis and the value of the other variable determining the position on the vertical axis.

Scatter Plot

Cluster analysis or clustering is the task of grouping a set of objects in such a way that objects in the same group (called a cluster) are more similar (in some sense or another) to each other than to those in other groups (clusters). It is a main task of exploratory data mining, and a common technique for statistical data analysis, used in many fields, including machine learning, pattern recognition, image analysis, information retrieval, and bioinformatics.

Cluster Analysis

A Pareto chart, named after Vilfredo Pareto, is a type of chart that contains both bars and a line graph, where individual values are represented in descending order by bars, and the cumulative total is represented by the line. The purpose of the Pareto chart is to highlight the most important among a (typically large) set of factors.

Pareto Chart

A Bullet Graph is a variation of a Bar Graph. Seemingly inspired by the traditional thermometer charts and progress bars found in many dashboards, the bullet graph serves as a replacement for dashboard gauges and meters. Bullet graphs were developed to overcome the fundamental issues of gauges and meters: they typically display too little information, require too much space, and are cluttered with useless and distracting decoration.

Bullet Graph

A Partition Layer Chart is a graphical display of clustering results, so called because it resembles a row of icicles hanging from the eaves of a house.

Partition Layer Chart Icicle Diagram

A candlestick chart is a style of bar-chart used to describe price movements of a security, derivative, or currency for a designated span of time. Each bar represents the range of price movement over a given time interval. 
It is most often used in technical analysis of equity and currency price patterns. They appear superficially similar to box plots, but are unrelated.
The dataset for a candlestick chart contains low, high, open and close values. The high and low values are visualized as the top and bottom of each stick, where the open and close values are reflected in the square inside.

Candlestick Chart

Bubble pie chart is a unique bubble chart that allows you to show/compare/relate performance across four paramenter sets instead of two. The third value determines the size of the bubble marker, the fourth by the % of pie while the other two are determined by the position on the axis.

Compound Bubble and Pie Chart

A fan chart,  is a chart representing family relationships in a tree structure. It features a half circle chart with concentric rings: the person of interest is the inner circle, the second circle is divided in two (each side is one parent), the third circle is divided in four, and so forth. Fan charts depict paternal and maternal ancestors.

Fan Chart (Geneaology)

A curved bar chart is a variation of bar chart where curved areas are used instead of rectangles. Height of each curved area is proportional to the values it represents. The curved areas can be plotted vertically or horizontally. One axis of the chart shows the specific categories being compared, and the other axis represents a discrete value.
Curved bar charts are often seen in modern infographics, but are criticized for being confusing and inaccurate compared to a normal bar chart, as the curved area actually only has one dimension, which is the height.

Curved Bar Chart

A Mekko chart (also called marimekko chart) is a two-dimensional stacked chart. In addition to the varying segment heights of a regular stacked chart, a Mekko chart also has varying column widths. Column widths are scaled such that the total width matches the desired chart width.

Marimekko Chart

Nested circles allow to represent hierarchies and compare values. This visualization is particularly effective to show the proportion between elements through their areas and their position inside a hierarchical structure.

Clustered Force Layout

Dumbbell dot plots — dot plots with two or more series of data — are an alternative to the clustered bar chart or slope chart.
A dumbbell dot plot can be used to visualize two or three different points in time, or to triangulate different viewpoints (e.g., one dot for Republicans and another dot for Democrats, or one dot for principals and another dot for teachers).

Dumbbell Plot

A radial heat map is a variation of heat map, where the table is aligned radially. A heat map is a graphical representation of data where the individual values contained in a matrix are represented as colors. Fractal maps and tree maps both often use a similar system of color-coding to represent the values taken by a variable in a hierarchy. The term is also used to mean its thematic application as a choropleth map. The term “Heatmap” was originally coined and trademarked by software designer Cormac Kinney in 1991, to describe a 2D display depicting real time financial market information.

Circular Heat Map

A stepped line graph (also called step chart) is a chart similar to a line graph, but with the line forming a series of steps between data points. A stepped line chart can be useful when you want to show the changes that occur at irregular intervals. For example, price rise in milk products, petrol, tax rate, interest rates, etc.

Stepped Line Graph

Alluvial diagrams are a type of flow diagram originally developed to represent changes in network structure over time. In allusion to both their visual appearance and their emphasis on flow, alluvial diagrams are named after alluvial fans that are naturally formed by the soil deposited from streaming water.
Variables are assigned to vertical axes that are parallel. Values are represented with blocks on each axis. The height of a block represents the size of the cluster and the height of a stream field represents the size of the components contained in both blocks connected by the stream field.
Alluvial diagram is a variant of the Parallel Sets but for categorical variables and often to display trends over time and phases.

Alluvial Diagram

Bumps charts are designed for exploring changes in rank over time.

Bump Chart

A three-dimensional scatter plot is like a scatter plot, but with g three variables.Provided that x, y, and z or f(x, y) are real numbers, the graph can be represented as dots in a three-dimensional Cartesian coordinate system. It is typically drawn on a two-dimensional page or screen using perspective methods (isometric or perspective),  so that one of the dimensions appears to be coming out of the page.

3D Scatter Plot

A chord diagram is a graphical method of displaying the inter-relationships between data in a matrix. The data is arranged radially around a circle with the relationships between the points typically drawn as arcs connecting the data together.

Chord Diagram

Hexagonal Binning is another way to manage the problem of having to many points that start to overlap. Hexagonal binning plots density, rather than points. Points are binned into gridded hexagons and distribution (the number of points per hexagon) is displayed using either the color or the area of the hexagons.This technique was first described in 1987 (D.B.Carr et al. Scatterplot Matrix Techniques for large N, Journal of the American Statistical Association, No.389 pp 424-436).
There are many reasons for using hexagons instead of squares for binning a 2D surface as a plane. The most evident is that hexagons are more similar to circle than square. This translates in more efficient data aggregation around the bin center. This can be seen by looking at some particular properties of hexagons and, especially, of the hexagonal tessellation.

Hexagonal Binning

Radial Line Graph is a part of radial graphs that takes data and render it as collection of data points wrapped around a circle. It is also mapping a list of categories from the minimum to the maximum of the extent of the chart. Radial Line Graph is rendered using a collection of straight lines connecting data points.

Radial Line Graph

A bagplot is a method in robust statistics for visualizing two-dimensional statistical data. The bagplot allows one to visualize the location, spread, skewness, and outliers of the data set. The bagplot consists of three nested polygons, called the “bag”, the “fence”, and the “loop”. The bagplot is sometimes defined as the multidimensional (bivariate) version of the box plot.


A ternary plot is a barycentric plot on three variables which sum to a constant. It graphically depicts the ratios of the three variables as positions in an equilateral triangle. It is used in physical chemistry, petrology, mineralogy, metallurgy, and other physical sciences to show the compositions of systems composed of three species.

Ternary Plot

A Waterfall Plot is a three-dimensional plot in which multiple curves of data, typically spectra, are displayed simultaneously. Typically the curves are staggered both across the screen and vertically, with ‘nearer’ curves masking the ones behind. The result is a series of “mountain” shapes that appear to be side by side. The waterfall plot is often used to show how two-dimensional information changes over time or some other variable such as rpm.
Not to be confused with the similarly named Waterfall Chart.

Waterfall Plot