How to Smart Map: Heat Maps
A simple guide to using density within ArcGIS Online
This quick guide introduces a fast, simple way to effectively analyze point data using heat maps within smart mapping.
Getting Started with Density
This guide introduces how to use the smart mapping style, heat map, to show density in your maps.
Smart mapping will recognize when a point layer is added to the map and by default the points will be symbolized by location.
Instantly I have a map showing where my data is. But let's go further! Heat mapping allows us to see the location and distribution of features. They use the points in the layer to calculate and display the relative density of points as smoothly varying sets of colors ranging from cool (low density of points) to hot (many points). Are you most interested in where a lot of points are located or where high and low values for a particular attribute are clustered? Heat maps can answer both these questions.
They are particularly useful when many of the points on the map are close together or overlapping, making it difficult to distinguish between features. Heat maps are also effective for displaying layers that contain a large number of points.
Heat Mapping can be broken into 2 simple steps
1. Select Heat Map style
2. Explore the options
Let's do an exercise and take our Minneapolis public 311 incidents and make a more helpful map with heat mapping.
Start by clicking Change Style to access the smart mapping options. Then select Heat Map to transform your points into a heat map.
Now click 'Options' to adjust the heat map style.
To change the color ramp being used in the map, use the Symbols button to see the options.
I'm going to select another color ramp which better suits the basemap.
Additional options include area of influence, transparency and scale range.
Now we can see a central location where the highest density of points is!
But what if we went one step further and used heat mapping on an attribute to show a statistically significant area.
By choosing case status, I can identify the concentrations of open incidents. This map tells a drastically different story!
Applying Heat Mapping
Tips and Tricks
Add the points back in on top of your heat map for pop up information and reference. Increase transparency so the heat map is still clearly visible.
Increase or decrease the area of influence to make the clusters larger and smoother, or smaller and more distinct.
To change how the colors are applied to the density surface, adjust the position of the two handles on the color ramp slider.
While smart mapping will come up with a useful default map for you, don't be afraid to adjust the settings to make a more informative map. Don't like your changes? No problem. Just hit 'Cancel' instead of 'Done' and it will revert to the previous setting.
Visit any of the sample web maps below for inspiration or documentation for reference to start mapping!
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