Color is a powerful instrument when mapping your data, because it can help create clarity about the underlying message your map shows. As the map-maker, you are the most valuable tool when creating a narrative around your data.
When working with your data in ArcGIS Online and Enterprise, choose the Change Style option to work with smart mapping.
Smart mapping helps you create beautiful and informative maps, quickly. It is a capability, that by default, sets the cartography of your map based on the significant values within your data.
There are many different color options available within smart mapping, and it is simple to adjust the map's colors to match the message you want to show with your data. Using color as a tool within your map can also lead to more clarity about your data. So how do you know which options to use?
This step is a mental exercise. It only takes a moment, but can help you later when you are making your color choices. Think of your map as the interface to your data. You have been tasked to create this interface, so it is important to be as clear as possible for your audience.
You want to relay an important message, so take advantage of color to tell your narrative, rather than just dumping data onto the map. Really consider why you are making your map:
No matter your purpose, make sure to think through what you are trying to relay to your audience. An important way to get the intended reaction out of your audience is to simply be conscious about what colors you use in your map.
By instinct, humans react to different colors, so therefore, color can influence the way people perceive the message being told by your map. For example, when a strong red is used alongside a strong green in a map, the map reader might associate the red as bad and green as good.
Seems simple enough, right? Almost.
Red doesn't always mean something negative is being shown by the map, just as green doesn't always mean something is good. Green can also be associated with money or nature, while red can be used simply to draw attention.
As the map-maker, it is important to consider what story you are trying to tell within your map, and the colors you choose can steer the way someone comprehends this story. Use your knowledge about the topic and your audience as you make your color choices.
Strong colors tend to incite strong emotion, while more subdued colors might subdue the overall pattern shown within a map. Each map is different, which is where your personal judgement as the cartographer comes in handy. Take a step back and think about the immediate story being told with your colors, and always consider the message your map needs to tell.
Keep in mind that your audience may only have moments to make a deduction based on your map, so you want to be as clear as possible.
The best foundation for an informative map is your basemap. The first thing you want to do before making color decisions on your features is to pick a basemap appropriate to your map topic. Smart mapping will offer color ramp options suitable for each basemap, so this is important as the first step.
When selecting a basemap, think about what you want to emphasize in your map. Basemaps provide a valuable reference for the world, so consider if you want your audience to understand something about the area surrounding your data, or of you want the focus to be on the data itself.
Are you mapping natural features? The Topographic or Terrain with Labels basemaps offer an informative backdrop to the map.
Do you want to emphasize your data with less focus on the background? Try the Light or Dark Grey Canvas options, which provide a subtle reference.
To select a global Esri basemap, use the Basemap Selector along the top ribbon in the Map Viewer:
The Living Atlas of the World also contains additional basemap options:
Basemaps also allow you to add transparency the same way you would with a data layer. Using this technique on the reference layer or the basemap itself can minimize distractions for your audience, and draws attention to the data.
Once you have chosen the foundation for your map through a basemap, its time to explore the color options within smart mapping.
Smart mapping is packed with tools and color options to help you tell a story about your data, with or without a cartographic background.
Let's dive in by looking at some basic ways to use color ramps:
Let's go through an exercise where we turn these street features into an interesting visualization about traffic patterns.
First, we will choose to map by Average Annual Daily Traffic, or AADT.
AADT tracks the amount of vehicles passing a particular street/location, and is used to pinpoint areas with high or low traffic volume.
The smart mapping default immediately displays an interesting pattern about the busiest roads in Des Moine, Iowa. We can see a freeway, the busy downtown area, and some of the main thoroughfares of the city.
By default, smart mapping will show you a High to Low Theme. This theme shows exactly what it describes: a color pattern distinctively highlighting the highest and lowest values within the data.
In our AADT map, this technique highlights the freeways and main city thoroughfares by using different intensities of color to represent the AADT. The busiest streets get a dark blue, while the streets with the lightest traffic are a light blue with a yellow tint.
To change the color ramp being used in the map, use the Symbols button to see the options.
Since the High to Low Theme is being used, we only see ramps which fit this pattern.
The use of a High to Low Theme is most appropriate when you want to emphasize the overall spread of values within your data. For example, if I am mapping income within my city, I might want to highlight the areas with the highest and lowest incomes so that I can find areas that might need help.
High to Low can be represented with a single color ranging from a light to dark (light blue to dark blue), or it can be shown with a light color and a dark color (yellow to green).
For this map, let's use our knowledge from Step 1 (Plan It) to think about our color choice for this topic.
We currently see blue colors representing traffic. What types of features might be associated with blue?
Water, sky, nature, cleanliness
While these colors would work without issue, it might not be the best way to represent a count of cars. Personally, what do I think of when I think of traffic and cars?
Smog, congestion, urban...
BROWN!
Instead, we can choose the brown ramp (highlighted).
While the map is showing the same pattern as before, the perception of the subject has slightly changed. This was done by simply changing the color ramp.
To recap, the High to Low Theme emphasizes the highest and lowest values within your data by using colors which range from a light to dark shade.
Next, let's look into another way of using color ramps.
Smart mapping offers another mapping theme which uses color to tell a story: Above and Below
To use this theme, use the drop-down menu to change the option being used by the map. It will automatically adjust the map to match the theme.
Like the High to Low theme, the Above and Below theme also maps your data exactly how it is named. It automatically centers your map around the statistical mean, and then maps all values above the mean as one color and all values below the mean as a different color.
Using Above and Below is a great way to "anchor" your map around a value. By default it uses the mean, but your knowledge about a subject could mean you anchor around a specific number important to the topic you're mapping.
You can see how this map has changed, and how the histogram now centers around the mean (or average) value.
Since the Above and Below theme uses a central value to anchor the map, the color ramps provided by smart mapping adjust accordingly.
You can see that the options have changed from when we used High to Low. Now, the color ramps show patterns where they diverge from a middle color, or they have a central break between two distinct colors.
For instance, the ramp the map is using has purple at one end, white for the centered values, and red at the other end.
As we did before, let's choose a ramp more suitable to the topic we are mapping.
Again, I want to emphasize the areas with the most daily traffic with brown.
But now that we are using the Above and Below theme, we can highlight areas with below-average traffic with a completely separate color. I see a ramp with an brown tint, so I can try that one.
Since we want the values ABOVE average to be brown, we can choose to flip the ramp so that the brown values show the highest traffic areas.
The map has transformed into a different narrative about the data. The brown areas clearly highlight the areas with the most traffic, but we also can see an emerging pattern about the least busy streets with the light blue color.
To recap again, the Above and Below theme offers diverging color ramps in order to show a map anchored around a central or specific value.
In combination with our choice of colors, the map can inform an audience about a different narrative than before.
As you just saw, small adjustments can make a world of difference within your maps. For more on this, the blog "6 Easy Ways to Improve Your Maps" covers some additional ways to make your story clear using the smart mapping options.
To review, there are 3 easy tips to help guide you on your map-making journey:
While smart mapping can create a valuable default map for you, these basic tips can help you create more informative narratives using your knowledge of the data. Smart mapping allows you to try new things and immediately see them in action before applying a change.
Ready to give it a try? Visit any of the maps listed below to start experimenting with the color options available in smart mapping.
Don't be afraid to get out there and play with the different options within smart mapping. You never know until you try!
Explore some of the maps featured within this story map. You can even open the smart mapping settings for some inspiration.
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