This document introduces some vocabulary that is essential to understanding representations.
A representation is a property of a feature class that allows you to specify and store a series of rules that dictate the way the features in the feature class should be drawn. A feature class can have more than one representation, allowing the same data to be displayed in different ways for different purposes.
A representation rule contains symbol layers and geometric effects to define how a group of related features in a representation is drawn. Representation rules can be stored within styles for sharing and reuse in other representations.
Representation symbol layer
Symbol layers are the basic building blocks of the representation rule and can be one of three types: marker, line, or fill. A representation rule must have at least one symbol layer but may have many to support complex depictions.
Geometric effects are optional components of representation rules. They alter the geometry of features dynamically when they're drawn to achieve the desired appearance without affecting the associated shape of the feature itself. This means that a complex view of the data can be achieved without affecting existing spatial relationships. Geometric effects can apply to just one symbol layer or globally to all symbol layers in a representation rule. Geometric effects work sequentially, so the dynamic result of one becomes the input for the next.
Marker placement style
A marker placement style defines how markers should be drawn with respect to the feature geometry. They are somewhat analogous to a geometric effect, but they are a required and integral component to a marker symbol layer.
Overrides are feature-specific exceptions to representation rules. They are stored and maintained in the geodatabase so will persist anywhere the representation is used. Overrides can also be made to feature geometry to modify the appearance of features without affecting the source geometry. Geometry overrides are sometimes called shape overrides.
A representation marker is similar to a conventional point symbol, but a representation marker is constructed from vectors and is directly editable on the Marker Editor dialog box. A representation marker is a required and integral part of a representation marker symbol layer, along with a marker placement style.
A free representation has its own representation rule not associated with any other feature, allowing full customization and control over appearance.
Representation control point
This specialized geometry vertex controls the phases of certain geometric effects in a representation rule.