Data visualization checklist: choosing between static maps and interactive geovisualizations

CPCS Transcom

February 1, 2022

Data scientists at CPCS turn lifeless data into rich visuals that our clients use as a decision-making tool. Here’s their visualization checklist to determine when to use static maps or interactive geovisualizations, as the choice isn’t obvious nor trivial.

To the point:

What is the message to convey?
How will your audience receive insights or communicate them to stakeholders?
How many distinct geographic extents do you need to communicate your message?
How many feature attributes do you need to depict for your communication objective?
To what extent does your data overlap spatially?
How frequently will your visualization be updated with new data?
What types of symbology and aesthetic techniques do you need access to?
Would an interactive geovisualization improve the overall business process or approach?

Good data visualizations tell a story quickly and concisely. The best ones get to the heart of the insight for better decision-making.

Maps are compelling because they can portray several multidimensional patterns at a time. While static maps are useful, interactive geovisualizations (IGVs) make data visualization even more compelling.

IGVs are typically maps where you can zoom in and pan around, thereby altering how much and in what fashion data is displayed. They may include additional elements that support data exploration and analysis, such as plots, tables, custom reports, or search functionality. The interactivity and synchronization of these elements open new possibilities and challenges for communication and insight.

Data visualization decision guide

1. What is the message to convey?

Review the analytical findings and patterns you have, or expect to have, and write a clear communication objective. This is the insight that you want the client to retain.

If you have a specific objective in mind, you’re likely familiar with part of a dataset and know how to interpret it or what to expect from the results of an analysis. Some examples are:

“Show me what assets are in my consortium’s jurisdiction.”
“Depict the AADT on my road network.”
“Explain the density of solar power potential in my region.”

An objective alone cannot fully suggest which visualization type is best. Keep following this checklist to assess your objective against more criteria.

If your goal is to enable general data exploration, you probably have heterogeneous or multifaceted data or datasets, and need to package it to be used and understood easily.

Typically, an interactive geovisualization is the answer in these situations, though there are various considerations to determine the exact form that this should take. Pay attention to items 6 to 8 in this checklist to learn about trade-offs and important considerations for developing an IGV.

2: How will your audience receive insights or communicate them to stakeholders?

Here are some common situations in which visualizations are presented:

“I’m submitting a report which the client will read later” – Only static maps can be embedded in word documents as of this writing.
“I’m giving a presentation to my client” – Static maps can be embedded as images in slide decks, while an interactive geovisualization could be embedded as a video. For a deeper dive into the insight afforded by an IGV, a live demonstration could be integrated into the presentation.
“I’m handing over a flexible tool to generate insight now and in future scenarios” – Only interactive geovisualizations empower the client to explore and synthesize the data on their own terms, in their own time and for their own purposes.

3: How many distinct geographic extents do you need to communicate your message?

This answer could depend on the area of interest. For example, some objectives may be communicated with a single state or province-wide extent. Other objectives may require a view of the extent of each county or administrative subdivision of the stakeholders. Corridors or sub-corridors, Special Economic Zones, and Port Areas may also be relevant geographic extents needed to show analytical results and meet your communication objective.

If five or more geographic extents are needed for your objective, an interactive geovisualization is likely the most appropriate solution. If four or fewer extents are needed, a static map is likely the most appropriate solution.

A special case is when the geographic extent should be determined in near real time. Interactive geovisualizations excel in this case regardless of the number of distinct extents, because they support panning and zooming operations that allow the user to change the extent as they see fit.

4: How many feature attributes do you need to depict for your communication objective?

Some datasets have many columns of information per feature. Any of these may be pertinent to the communication objective of a visualization. For example, the screenshot below was taken from an IGV whose communication objective was to summarize information about hazardous material handling facilities for first responders. Each point has more than 12 pieces of information providing insight to the map’s users.

If four or more attributes of the same feature are relevant, an interactive geovisualization is likely the most appropriate solution, while a static map is likely the best solution if three or fewer attributes are relevant. The choice of this threshold is informed by the aesthetic limitations of combining multiple visual variables.

5: To what extent does your data overlap spatially?

Synthesizing insight often means making connections between multiple distinct datasets. When these datasets overlap, it can create confusing visuals that undermine clear communication. Both static maps and IGVs can address this spatial overlap challenge, albeit with different limits.

Static maps can be embellished with insets and/or leader lines to address problematic data overlap. For example, consider the map of California’s Bay Area below. Two inset maps have been added to show more detail where railroad grade crossing locations are close enough that their symbols overlap.

Too many regions or features which require this treatment can overwhelm the map, leading to the geographic extent challenges described in step 3. However, insets and leader lines allow you to extract more mileage out of static maps if other circumstances or criteria in this checklist point you in that direction.

Interactive geovisualizations allow clients to zoom to different map scales. By zooming in, the user can explore denser areas more closely at a resolution where data overlap ceases to be an issue. Most IGVs can also show or hide a given layer so users can remove any layers that overlap. Toggling layers on and off can aid in internalizing the relationships between spatially correlated data layers in a way that static maps cannot.

6: How frequently will your visualization be updated with new data?

Datasets may be dynamically updated or republished periodically. If your communication objective concerns a single snapshot in time, a static map is a suitable solution as long as the frequency isn’t more often than once per day.

If your vision is to update your map frequently, an interactive geovisualization may be the suitable solution, because they can be configured with a direct connection to a dataset’s source. As such, when the source is updated, the IGV is updated as well. This makes IGVs much more suitable for situations where it is important to have rapid access to the most up-to-date insight.

7: What types of symbology and aesthetic techniques do you need access to?

Interactive geovisualizations are generally implemented with application development tools which restrict the options available for executing a map’s aesthetic design. If you desire complex or specific symbols and particular graphic techniques to achieve your communication objective, a static map is likely a more suitable solution, since the GIS and graphic design software used in their production affords more creative flexibility.

8: Would an interactive geovisualization improve the overall business process or approach?

There may be additional cost or training considerations to implement an IGV. This investment is worthwhile if it meets the client’s needs. There are two factors to consider:

Learning curve and accessibility. Using and reading a static map is more straightforward, as the typical file formats for these are familiar to many and reading them takes only a few seconds to capture the whole view. On the other hand, interactive geovisualizations have a learning curve as users adapt to the controls and interfaces that enable interaction with the map, typically zooming, panning, querying, or other operations. The target audience of any interactive map should be prepared to perform these interactions, either with the help of training materials or based on prior knowledge.

Hosting and maintenance. Once exported, static maps incur no ongoing maintenance costs provided the visualization and data do not change. Anyone can store the file or image of a static map on their local computer. By contrast, interactive geovisualizations rely on a more complex behind-the-scene infrastructure to run and maintain, including web server setup and program updates.

Leaving an impression

Interactive geovisualizations offer exciting new opportunities for communication and insight that often leave a lasting impression on clients and stakeholders. The guidance in this checklist has introduced you to various dimensions of the decision to pursue interactive geovisualizations or static maps, and provides a framework for thinking through this choice in consultation with clients, consultants, analysts and cartographers.

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