Available with 3D Analyst license.
You can apply size to your point feature data based on an attribute field, an expression, or random values. Applying different sizes to point features can be extremely useful in cases when you want to display features based on their actual size, for example, the size of trees or the magnitude of earthquakes.
Applying size to point feature symbology
In ArcGlobe, if you have point feature data with an attribute field that contains the size values, you can symbolize your points by this size field. Each marker symbol is sized individually by the size specified in the attribute field.
If your point feature data does not have size values in an attribute field, you can apply random sizes to the symbology. You can also supply an expression by using the Expression Builder calculator. Expressions are a way to provide simple arithmetic operations to add, subtract, multiply, or divide the value in the attribute field by a constant value. Or you can just use a constant size value.
To size feature symbology without taking the size from a field, you can double-click the marker symbol to edit its properties, including setting the size property. However, if you then choose to apply size using a size attribute field, expression, or random values, all symbols will be drawn based on the newly derived size values.
In the graphic below, the left side shows point features without any size specified. The right side of the graphic shows the same point features, but they are displayed using size values taken from a numeric field in the attribute table.
You can also use the size-based symbology for creating feature representations of your data. See Understanding representations and Resizing feature representations in the ArcMap Help for more information about representations.