How to create a swing arrow map

Swing is a popular election variable to visualize in a map. It shows the extent of change in voter support, typically from one election to another, expressed as a positive or negative percentage. To create your own swing arrow map with our Projection map template,

    Select our arrow map starting point
    In the Points sheet of the Data tab, upload your data. It should have a longitude and latitude as well as a Size by column and, optionally, a Color by column. 

    TIP: Make sure you have some negative and some positive values in your data. Negative values will point left, positive values will point right.

    You can also supply different metrics to display within a dropdown or filter by adding multiple to the Size by column.


    In the Data tab, navigate to the Points layer settings. Here you can define:

    • The arrow angle in degrees: This sets the angle (clockwise) for positive values (between 0 and 180)
    • The maximum length in pixels: This sets the max length (upper range) of arrows
    • The arrow flip mode, choosing from vertical and horizontal: This sets how the arrow angle is flipped. If vertically, then the negative arrow angle is the negative value of the positive arrow angle. If horizontally, the angle is 180 minus the positive angle. Defaults to vertical.
    • The maximum value
    • The fill opacity
    • The stroke width, opacity and color


    You can also change how the arrows are colored:
    Screenshot 2022-10-28 at 12 29 54

    If Color by value is enabled, the arrows are colored depending on whether their values are positive or negative. You can set the colours manually for both. Otherwise, arrows are coloured by the Points > Color by column (if set) or a customizable default fill.


    Finally, you might want to tweak your legend to set the positive and negative labels and adjust the size of the arrow icons. You can do this in the Legend > Arrow legend settings.

Get started with your own arrow map now! ยป