The size of symbols can be adjusted dynamically across their visible scale range to reduce visual density at smaller scales while retaining an appropriate relative size at larger scales. Typically, these differences in symbol size are subtle across the visible scale range. You want to maintain a symbol size appropriate for the feature density at each scale without introducing noticeable increases in size.
An example is adjusting the size of the symbol used to draw streets. At larger scales, streets should be appropriately wide as they run between buildings. If they are too narrow, they look unnatural relative to the buildings or other nearby features and will not adequately represent the landscape. At smaller scales, streets should be narrow enough to not interfere with other more important features, yet still give an indication of urban density.
Scale-based symbol sizing is only available in 2D maps. It is not available in 3D scenes.
Apply scale-based sizing to a symbol
To use scale-based sizing, complete the following steps:
- Highlight a feature layer by clicking its title in the Contents pane.
- Under Feature Layer on the Appearance tab in the Drawing group, click Symbology to open the Symbology pane.
- Click a symbol to open the Format Symbol pane.
Alternatively, you can click a symbol in the Contents pane to open the Format Symbol pane directly.
- On the Properties tab, on the Symbol tab , check Enable scale-based sizing.
A slider appears below the Size property for point symbols, the Line width property for line symbols, and the Outline width property for polygon symbols.
The stops on the slider are derived from the map scales. The slider extends across the complete scale range, from an infinitely small scale (zoomed far out) on the left extreme of the slider, to a large scale of zero (zoomed far in) at the right extreme of the slider. The dark part of the slider shows the visible scale range of the symbol class or layer. (If the visible scale range is not constrained to specific scales for the corresponding feature class, the entire slider is dark.)
- Click a scale stop and define the symbol size at that scale in the Size (or Line width, or Outline width) property box.
You can click and drag stops to define the size at a different scale. The point symbol size varies linearly in size between stops.
- Click the Add size stop button to add new stops based on the defined map scales, or click along the slider.
To learn more about setting map scales, see Map scales and scale properties.
To learn other ways to adjust the size of point symbols, see Vary symbology by size.