How To Prepare a Heat Map Data Visualizations Presentation

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Making sense of geographical and categorical data to understand information of variable importance, requires a visualization type that can help identify the phenomenon by highlighting key bits of the data. Heat maps are used to identify and interpret such information. This article will introduce the concept of a heatmap, which are the popular variations, and how they are used in real-case scenarios.

What is a Heat Map?

A heat map is the visualization of data that represents the magnitude of a value in a color code ranging from minor to major intensity. The name metaphor is born in the technique used to depict heat; blue means cool, red means hot, and intermediate temperatures are coded as the gradient between those two. The variation of color is often portrayed in intensity and hue, highlighting the extent of the phenomenon to make it easier to interpret.

There are two main types of heatmaps:

The Spatial Heat Map: Represented with a canvas that represents a two-dimensional space; it can be a geographical map, a web page, or other cartesian representation.

Grid Heatmap: This type of heat map displays the magnitude of a phenomenon using a two-dimensional matrix. Columns and Rows categorize a cell (the location) and the cell’s color code defines the phenomenon’s value intensity.

Heat map Visualizations and How To Present Them

While we can broadly categorize heatmaps as spatial and grid, there are different ways in which these map types can be instantiated, and used in visualizations and charts. Through the following heat map examples, we provide recommendations to present your heat map analysis.

1. Geographical Heatmap

A geographical heatmap is a spatial map to visualize data according to geographical location. This can be done to show the phenomenon’s intensity, such as weather trends or demographic information. The heatmap quality will be determined by the density of the dots in the map, and the color spread. This means that the more latitude-longitude dots you have on the map, the better the representation of reality. Precision geographical heat maps are created with mathematical-statistical tools, like R, Python, or more specialized tools, and require a lot of data.

For example, we can take the NASA projection of the average temperature of the world for 2100. If you need to present a heatmap of this level of detail, our recommendation is that you generate it in a statistical tool and include it in your presentation as an image. Source: NASA

a slide showing an average temperature heatmap
Slide featuring the heatmap of the world’s average temperature by 2100. Heatmap by NASA.

When creating presentations that do not require “scientific” precision, you can create a geographical heat map using a low-resolution representation of the map, that will allow the presenter to instantiate the datasets with fewer data points.

For low-resolution maps, you can use pixelated maps or low poly maps.

A real-life example would be the global sales of a company, distributed around the world.

example of a slide showing a global sales heatmap
Note: In this case where scientific precision is not required, and the presenter wants to showcase the global distribution of amounts using color codes, each of the pixel groups can be selected and colored by gradients within PowerPoint. Just using the spectrum template.

Choropleth Maps – An alternative to Geographical Heat Maps

By formal definition, the Choropleth Maps differ from the geographic spatial heat maps we described earlier. Mainly because it does not use pure spatial information. It uses predefined segments in the map (area/region) to aggregate the phenomenon variable. This aggregation makes it simpler to understand and it has become even a more popular tool in business, politics, and social studies.

You can create Choropleth Maps using Excel (Office 365 version) or with SlideModel’s PowerPoint map templates, which provide data-driven Choropleth for all versions of Excel and PowerPoint.In the following example, we used our editable us map and applied the US Census data from 2010 to 2019.

a choropleth heatmap of the US census data from 2010 to 2019
US Census data shown in a Choropleth heatmap

The map uses a data-driven excel provided by the template. The census data was loaded into the excel sheet. Then we placed the map in the PowerPoint presentation just dragging and dropping.

a Excel spreadsheet with data to generate a choropleth heatmap
Excel spreadsheet with the data used for the Choropleth heatmap

2. Bubble Chart Heatmap

Bubble charts are a generalization of the scatter plot. Each point is located on a cartesian axis (X, Y) and a circle is created in it. The size of the circle is a third dimension in the visualization, used to represent a magnitude. When complemented with a color gradient, a fourth dimension can be represented as a heat map.

Bubble charts can be used both spatially and in the form of a grid. 

For example, let’s see an example of the analysis of marketing campaign results. The following heatmap has the following dimension:

  • a. on the X-axis the days the campaign was running
  • b. on the Y-axis an effective KPI
  • c. the size of the bubbles represents the monetary cost of the campaign
  • d. the color of the bubble is a gradient that determines the times the campaign was displayed to the audience.

This visualization helps marketers spot the campaigns with the best monetary performance and without abusing display impressions.

a bubble chart heat map used in marketing performance campaigns
Bubble chart heatmap to display campaign effectiveness by medium

3. Matrix Heatmap

The Matrix heatmap uses a two-dimensional matrix to represent the phenomenon. This is basically a grid map with rows, columns, and cell colors to represent data. The matrix heatmap depicts the magnitude of a phenomenon based on a 2D matrix, with each category or trait representing a dimension (e.g. year, month, and temperature).

An example of a matrix heat map is the following analysis of the sales team. Each row represents a sales team, each column represents a month of the year. Each cell represents the amount of sales completed, with a gradient coding.

Matrix heat map of sales performance
A matrix heatmap with sales performance by teams per month

4. Clustered Heatmap

Clustered heat maps are a specialization of matrix heat maps; generally used in medicine, biological studies, and mathematics. Their purpose is to aid in the visual comparison of sample sets. To understand the structure, everything starts with a matrix heat map, where columns are “measuring sets”, and rows are the measured variable. Each cell contains the magnitude measured for the pair set-value. Then a clustering algorithm is applied to create Dendrograms, first for the variables (rows), later for the sets (columns). The clustering algorithm is out of the scope of this article, but we will use an example to understand the process of creation assuming the dendrograms are created by a black box.

A common use case we can describe is the comparison of laboratory tests of patients. Each column of the matrix will represent a patient. Each row will represent a variable measured. Each cell will be the magnitude of the variable for the patient. 

The first image shows the matrix heatmap, without the clustering:

Usage of matrix heatmaps in the pharmaceutical industry
A matrix heatmap used in laboratory tests

The second image represents the clustered heatmap once the dendrograms have been applied and the rearrangement of the matrix has been applied, according to the clusters.

An example of a clustered matrix heat map in the pharmaceutical industry
Clustered matrix heatmap for pharmaceutical industry usage

5. Correlation Heatmap

Another form of the grid heatmap is the correlation heatmap. This visualization is used to interpret the correlation phenomena of a set of measured variables. 

In the columns and the rows, the variables are displayed. Each cell represents the combination of the row variable with the column variable. This matrix is the cartesian product of the variables set. Each cell contains the calculated correlation between the variables. Correlation algorithms differ, but the correlation heatmap stays the same for all of them. As a particular structural behavior, the diagonal of the matrix has the correlation of one variable with its own, which is always 1, and the number of columns is the same as the rows, so it is a square matrix. A correlation is the same below the diagonal, or above, a triangle is used.

You can easily present a correlation matrix using a PowerPoint table as shown above and add the colors based on your coding.

Slide showing a correlation heatmap
Example of a correlation heatmap slide

When dealing with a large number of variables, the suggestion is to use excel, as you will be able to embed the result in your presentation and control several aspects of the table such as colors, layout, and display. 

6. Abstract Positioning Heat Map

Abstract positioning heatmaps are those where the spatial canvas is not a geographical map, but another kind of plane that wants to be analyzed by a ranging phenomenon. The positions in the plane are determined by a cartesian X, Y-axis; the plane is set as a background, and the phenomena are placed with the intensity defined by the color code selected. To better understand these heat maps, we will drill down into two popular examples.

a. Web Heatmaps

Web heatmaps have become very popular to understand user behavior on web pages. With the modern javascript libraries that allow tracking users’ clicks and navigation in the browser, webmasters are able to record this information and summarize it over a static canvas of the web page. The heatmap consists of using the web page or application as the canvas and placing in a new layer, the clicks and movements of the users using simple X, and Y positioning. To picture an example, you can see how users interact in the SlideModel Homepage in the following web heatmap:

web heatmap usage to track user interaction with a homepage
A web heat map showing user interaction on our homepage

The color code is intuitive. The nearer to reading, the more concentration of click. Nearer to green less concentration.

Web heatmaps need to be created with special tools. In order to present results, we suggest generating a high-fidelity heatmap and placing it as an image in the PowerPoint Presentation as an example.

b. Risk Heatmaps

Risk heat maps are very popular in the project management space. Conceptually is a simple chart, with X-axis denoting the impact of the phenomenon and the Y-axis representing the likelihood of occurrence. A simple color code is defined for the range where 0 is green, the midpoint is yellow and higher points of impact occurrence are red. With this gradient definition, a colored heatmap is created as the canvas background. Over the canvas, the different risks analyzed are categorized, and then action and plans are defined to take them from the start point in the heat map to the desired location of lower impact occurrence.

Using SlideModel’s Gradient Risk Matrix, you can create your own Risk Heat Map in PowerPoint.

How to Present a Heatmap Analysis to an Audience

The following sequence of suggestions will help you structure your heatmap presentation. It covers the pillars your message will need to address for everyone to understand your heatmap visualization and how they were interpreted to draw conclusions.

Step 1 – Introduce the data (observations and variables)

Before you show your heatmap to the audience, it might be necessary to explain the data, how observations are recorded, over which spatial space will be placed and which are the magnitudes of measurement. Instead of displaying the actual map, you can perhaps use a snapshot in your introductory or title slide to give a taste of what’s coming.

Step 2 – Start with a Complete View of the Space

To explain your heatmap, you can begin by showing a complete overview of the map. A bird’s eye view will help you place the spatial axis over it, and if needed, is the memento to address any caveats about precision and assumptions over the map. 

For example, if you decide to go with a pixelated world map, instead of a geographic map, you can explain how many points will represent the volume of the area, or if the location of the measured value is approximated.

Step 3 – Highlight the Phenomenon

Once you have explained the different dimensions in the heatmap you need to explain the phenomenon being colored. Explain the color code and the gradient selected. Make sure the range is clear, and what you plan to state in your thesis. If you are trying to find similarities in the data (when you use correlation heatmaps or clustered heatmaps) explain the grouping criteria of colors. If you are trying to explain intensity or lack of it, explain the criteria of high and low. Even though colors are generally related to the same metaphors (red = hot, blue = cool) explaining the metaphor applied is always recommended.

Step 4 – Explain the Map for Comparison and drill up/down

If the map shows a small area or you need to present a small set of data, even a single slide might suffice; however, for more complex maps, you can break down the phenomenon by focusing on part of the map as you present your slide. 

For example, suppose you represent a geographic spatial map showing a weather phenomenon. In that case, you can show the areas most affected by the phenomenon, followed by those least affected, to create a comparison. For this purpose, you can divide the map into multiple slides or use Slide Zoom in PowerPoint. 

When using Choropleth Maps, it is common to drill down from Regions, into sub-regions. As explained earlier this visualization is biased by the fact that a complete region is the aggregation of values of sub-regions. So it is wise to include in the analysis some kind of drill down that might spot certain behavior along the borders of regions.

Step 5 – List the insights that the heat map provides

After navigating the heatmap, focus on presenting the identified insights. For example, in the scenario of a web heatmap presentation, identified insight might be how many times users press a button, or how they ignore certain call-to-actions on a web page. In a correlation heatmap, some variables might show a high correlation through a big colored space, showing this associative force. Another example of insight could be comparing heatmap snapshots, for example, global temperatures in 2000 vs global temperatures in 2020, and how the heatmap shows the change over time.

Step 6 – Concluding Your Heatmap Presentation

You need to conclude your presentation with the formulated hypothesis, how the heatmap provides insights, and how they can be interpreted to draw conclusions or new hypotheses.

Heatmap Tools

Different tools can be used for creating and presenting heatmaps. We have listed a few tools that you might find helpful in creating a heatmap.

Construct a Matrix Heatmap in PowerPoint

You can create a grid heatmap in PowerPoint by either constructing rows and columns to form a plain  PowerPoint Table or using third-party PowerPoint templates as the ones provided by SlideModel. Starting from a template will help you save time, applying a professional layout without the hassle of structuring the whole slide’s visual look and feel. Just download the grid matrix you liked and fill it with your values and grid colors.

using a matrix heat map in PowerPoint
Example of a Matrix Heat Map with a PowerPoint template by SlideModel

Charticulator by Microsoft

Charticulator is a free tool by Microsoft for creating different types of dynamic visualization. Heatmap is one of the types of visualization that you can create in very simple steps. The most important value about this tool is that the visualizations you create are data driven, so if you change the dataset, the visualization will adapt accordingly. You can use your data to create charts and export them as an image, HTML, Power BI custom visual, and a Charticulator template. We recommend generating image charts and importing them into PowerPoint.

For example, we decided to create a very simple matrix heatmap. For this we used the Latin America demographics dataset of the World Population Prospects. United Nations. 2019.

Step 1

We start Charticulator with a new chart:

create a new chart in Charticulator for heatmap

Step 2

We import the csv dataset. You will see a preview:

importing dataset of demographic data in Charticulator

Step 3

Once you imported the dataset, you will see in the left pane, the dimensions (named Rows and Columns). Drag the Row dimension to the Y axis of the editor, and drag the Columns dimension to the X axis:

drag dimension from dataset to heatmap chart

Step 4

Once you have the dimensions, you need to build the shapes to represent the values. Charticulator calls the elements “Glyphs”. Go to the glyph editor and create a rectangle. This shape will hold the value of the X,Y position.

Charticulator create glyph for heatmap

Step 5

Select the shape in the glyph editor (a menu with the layers section will appear). To configure the heatmap coding just drag the “Values” metric in the left pane, into the Shape Style Fill.

Drag values to Glyph fill style

Step 6

Select the “SUM” metric function, then select the gradient coding of your choice.

Charticulator customize heatmap color coding

Step 7

Customize the final details, and finally export to SVG

Charticulator export in SVG

Step 8

Import the heatmap in PowerPoint as an SVG object.

import Charticulator heatmap into PowerPoint

Tableau

Tableau is a business intelligence and data analysis platform. You can visually represent different data types and present them using different display possibilities. Tableau enables end-users to create and present heatmaps. 

Users can create heat maps in Tableau using highlight tables that are used for categorical data comparison using colors. You can import your data in tableau and use drag and drop to create highlight tables as heatmaps. Once you create your heat map (spatial or grid) you can include it in your presentation through an embed.

Learn how to embed tableau in PowerPoint with our tutorial.

Power BI

Power BI is a powerful tool from Microsoft that allows creating visualizations with a variety of data sources. Among their core library of visualizations, it provides geographical heat maps, choropleth maps, Bubble heatmaps, and Grid heatmaps.

If you use PowerBI desktop you can export the visualizations as Images or Vectors, the latter being extremely customizable with your Presentation theme. If you use the PowerBI service, and you publish your visualization in your account, you will be able to embed it in PowerPoint using the PowerBI Add-in, which now is part of Office 365.

Spatial Heat Maps for Excel

Geographic Heat Maps and Choropleth maps are part of Excel charts. You can create the heat maps in excel and embed them in your presentation as any other kind of chart.

How to insert a Heat Map from Excel to PowerPoint?

PowerPoint allows you to embed your Heat Maps made in an Excel spreadsheet. Thanks to this functionality, you will be able to present your heat maps in a professional way and with accurate data.

Final Words

Heatmaps, be they spatial or grid heatmaps, can be extremely powerful visualizations to represent the intensity of a phenomenon.

How a heatmap chart is used depends on the type of data used and the kind of heatmap constructed for its representation. Heatmaps can be easier to interpret than many people might think. However, accurately plotting your heatmap requires careful consideration. Tools like Power BI, Tableau, and Charticulator can help you construct heatmaps from existing data.

Chart Templates, Heat Map, Presentation Approaches, Presentation Skills
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