What is a map chart?
A map chart allows organizations to position data or visualize spatial relationships using geographical context. They facilitate tagging of specific metrics against geographical locations. These charts have very specific uses, and require users to have geographical regions as part of their data. This is crucial for comparing values and showing various categories across different geographical regions. Examples of geographical regions could include postal codes, countries, or state regions.
Example of a map chart
The figure below is an example of a map chart. It is created using feature layers consisting of interactive shapes. The different states in the US form the different parts of the map. Users can interact with these states to find out more information, which are important for visualizations. The different colors represent different quantities and how something is represented across a state. Similarly, users can use maps with markers to show specific details in a topographical or spatial context.
Chart maps are visualization tools that can achieve some major data presentation goals. However, they cannot be used to tell all types of stories, making it important for users to understand when and why to use them.
When to use map charts
Individuals and organizations commonly use map charts when they need to comprehensively visualize data and compare it across regions for strategic decision-making purposes. Map charts provide important configuration options that help users visualize regional data and turn it to useful information. Maps are a great tool to help viewers to understand size, location, and distance.
A map chart is commonly used during elections, to show the outcomes of voting in each state. During the pandemic, map charts were used to show the spread and density of COVID infections.
Map charts are effectively used when the data is tied to specific locations. These locations could include specific business centers or marketing areas. If the data does not have geographical information recorded, it cannot be presented as a map chart.
While they are a great tool, there are very specific circumstances when they are useful.
Showing geographical changes across data
Map charts are useful when there is a need to look at performance of a specific store or marketing area. For instance, is the same advertisement working effectively in New York as it does in Dallas? Is there a store that performs better than others in a chain?
Map charts can help to visualize results showing a distribution. For instance, mapping can help to show the number of restaurants near a sporting facility, the number of burglaries around a specific center, or where customers live in proximity to their nearest store.
Showing only matched items
When users identify the need to single out and show only relevant regions for which critical data exists, map chart tools will help to show only matched items. Map charts are important when there is a need to zoom into selected regions depending on the available data and hierarchy filtering needs. So for instance if a manufacturer needs to see which factories are performing according to targets, the map will only display the locations of facilities that are not meeting targets.
When interaction is required
Map chats allow for user interactions. Options commonly available in the map's panel include the zoom in and zoom out, home, search, and grab areas that allow users to interact with the map. This is ideal if there is a need to drill down into specific geographical data.
Best practices when using the map charts
As with all charts, there are a number of best practices to follow in order to create the most helpful and accurate visualization.
Identify target audience
It is important to identify the target audience and their needs before creating map charts. Understanding the target audience is crucial and influences data vizualiation and information presentation for maximum efficiently. This helps to ensure that viewer’s interpretation does not differ significantly from the intended purpose.
The map creator should ensure the dataset is clean before converting it to map charts. Data cleaning should involve filtering potential inaccuracies in data sets. Data cleaning positively influences the outcomes and quality of map charts. Things like ensuring that there is consistency across naming is important. Is it the United States, or the US? If there is a variation across naming/ metadata, the chart will be useless.
Effective labeling is critical for enhancing data visualization. It ensures that users can easily identify the most significant values and patterns in map data. Users can easily identify unique points of significance critical in strategic decision-making.
Data visualization design
It is crucial to ensure that users can easily comprehend the information the map chart intends to convey. Emphasizing important points will direct users' attention by providing visual cues. This can be done in a variety of ways but using color gradients, as in heatmap contours, is the most common.
Formatting map charts for accessibility
It is important to ensure the readability of the visualized data in map charts. Effective formatting of the map charts ensures consistency and clarity in the map's design aspects. Formatting involves eliminating all the unnecessary information that could draw the user's attention from critical context.
The map should not be over-crowded with too many data points or overlapping markers, text should be legible, and important geographical borders should be easy to see.
Making use of color, shapes, and mapping points
The color, shapes, and mapping points are important visualization tools in map charts. The tools can help to convey critical information effectively using the different combinations. Use of color is vital to clearly convey information. For instance, with election data, choice of red or blue states is a very logical choice. However, when presenting information like the percentage of people who prefer winter to summer, using color choice and gradients can help make the chart more intuitive. In Florida, if 90% of people prefer summer, the map can show this in a bright red color, whereas in Maine, if 90% of people prefer winter, a dark blue can show this.
Types of map charts
Scatter maps enable users to visualize geographical data on a map as data point markers. They involve using different colors and sizes to distinguish data points on a map. Geo-coordinates are also used to display scattered markers in a geographic area on a map. Scatter maps allow creators to present details and to add value to a given work.
Bubble maps are variations of the scatter map charts in which bubbles replace data points. Circles or bubbles of different sizes represent the region's numeric value. One bubble is used to represent one geographic coordinate or region. Bubble maps are useful when users have a full list of geographic coordinates and a list of regions.
A map-pie or pie chart maps combine pie chart data and map in data visualization. It is a variation of scattering map charts with pie charts representing the data points. Pie maps involve using pie charts to show categorical data proportions of given features, making it easier to visualize locations and their numerical proportions.
Bubble pie maps are a variation of the pie chart maps in which bubble pies represent data points. The values inserted in the size field column determine the size of the pie chart. It is a unique bubble chart that enables users to compare and relate performances across more than two parameters.
Filled maps are chart types that allow users to represent different geographic regions on the map with a given measure or dimension criteria used to color specific areas. This type of map chart uses patterns, shading, or tinting to show proportionate differences of values across different regions or geographical areas. Filled maps help to display the relative differences with varying shading strategies quickly.
Geographic heat map
Geo heat maps refer to the geographic heat maps, interactive visualizations displaying users' data points on the real map to signify low- and high-density areas. Important fields in geographical heat maps include the data point's latitude, longitude, weight, and labels.
When to not use map charts for data visualization
Map charts are invaluable sources of insights for strategic decision-making. However, they are not always useful tools or the most appropriate choices when designing data visualizations.
Data does not contain geographic information
Map charts are used to map data containing geographic components. They should be used should to communicate relationships or comparisons of discrete geographic areas like countries, areas, or specific coordinates.
Other more informative options available
Avoid using map charts when alternative methods exist to visualize data. For instance, graphs or other charts could be used in situations where other factors such as age, race, gender, or socioeconomic data should be used alongside geographic variables.
Such cases may occur if map charts do not make data visualization any easier or in cases where map chart visualizations are no more useful than a source data table.
Features of map charts
Longitude and latitudes
These include the list of variables available to serve longitudinal or latitudinal values.
Some notable layers include the feature, marker, map, and image layers. The interactive layers allow marking to take effect, one layer at a time. Examples of layers include the USA states' layer as a feature layer, standard map as a map layer, and sales data as a marker layer.
Primary title and subtitles
These features largely comprise the chart title and subtitles that should display underneath the map chart title.
The feature provides the slider for each layer. This sets the zoom range to ensure that the layer is visible depending on the user's needs. It can hide layers with excessive details to enhance zoom visibility.
Benefits of map charts
Using a map chart can be extremely helpful in a number of scenarios. They are incredibly intuitive to understand and can explain data in a glance.
Population and market distribution
Map charts can help business owners and organizations analyze and classify consumers from different regions or geographical markets on a map. Chart maps can improve understanding of consumption, lifestyle, shopping habits, and interests based on regions.
Forecasting market capacity
Map charts can help organizations and business owners understand sales revenues and resource requirements per region or map outlet. These organizations can then use the map charts to predict the market's capacity and influence resource allocation depending on the regions with the better expansion or growth potential.
Map charts can enhance organizations' supply chain management and logistics path planning. Maps can enhance visualization, improve understanding of the order distribution, and assess storage options. In turn, this can help in optimizing logistics routes.
Determination of chain store locations
One of the important strategic decisions that business owners have to make is the location of chain stores and business spaces. Map charts can help decision-makers enhance the visual display of critical indicators such as store capacities and passenger flow. Such information can then help in conducting market planning.
Challenges of using map charts
Despite their amazing benefits, there are challenges when using map charts.
Human errors and bias
Human errors and bias could lead to map distortion. There is potential for human error and information distortion. Data selection should be done carefully or the map could display biased outcomes.
Improper design issues when creating chart maps could lead to confusion in communication. It is wise to remember that maps are flawed to begin with; the world is round. When the world is presented in a flat, 2D image, it stretches out some countries in order to ‘fit’ the image. For instance, Africa is 14 times larger than Greenland, but when viewed on a world map, they look to be about the same size.
Map charts are rarely the answer
Map charts are the eye candy of the chart world. They are very attractive and easy to understand, but they offer no depth or explanation for their contents. In order for an organization to use a map chart successfully, they must:
- Choose their data wisely. Should this be presented in another format?
- Maps cannot communicate information such as time. Consider another format if this is vital to impart
- Limit what is displayed; too many colors, markers, or layers of information occlude what is important
- Allow details to be included in point-and-click functions
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