ArcObjects Library Reference (Carto)

UniqueValueRenderer CoClass

A unique values renderer where symbols are assigned to features based on an unique attribute values.

Product Availability

Available with ArcGIS Engine, ArcGIS Desktop, and ArcGIS Server.

Description

Use this object to symbolize features based on the values of one or more attribute fields to show categorical difference.

Supported Platforms

Windows, Solaris, Linux

Interfaces

Interfaces	Description
IDisplayAdmin (esriDisplay)	Provides access to members that control display administration.
IExportSupport	Provides access to export support members.
IFeatureRenderer	Provides access to members that control functionality common to all feature renderers.
IFeatureRendererUpdate	Provides access to members that control functionality common to all feature renderers.
ILegendInfo	Provides access to members that control legend information provided by a renderer.
ILevelRenderer	Provides access to members that control the drawing of symbols for features, where symbols are separated into levels, and each level drawn separately.
ILookupLegendClass	Provides access to functionality for looking up a renderer's legend class via a feature.
ILookupSymbol	Provides access to functionality for looking up a renderer's symbol via a feature.
IPersist	Defines the single method GetClassID, which is designed to supply the CLSID of an object that can be stored persistently in the system. IPersist is the base interface for three other interfaces: IPersistStorage, IPersistStream, and IPersistFile.
IPersistStream (esriSystem)
IRendererClasses	Provides access to members that provides the information of layer annotation classes.
IRotationRenderer	Provides access to members that control the drawing of rotated marker symbols based on field values.
IRotationRenderer2	Provides access to members that control the rotation of marker symbols based on field values, expression, or random. Used for all symbols, not just 3D; used for all apps, including ArcMap.
ISizeRenderer	Provides access to members that control the drawing of sized marker symbols based on field values, expression, or random.
ITransparencyRenderer	Provides access to members that control the drawing of features with varying transparency, where transparency is determined by feature values.
IUniqueValueRenderer	Provides access to members that control a renderer where symbols are assigned to features based on unique attribute values.
IUniqueValueRenderer2	Provides access to members that control a renderer where symbols are assigned to features based on unique attribute values.
IXMLSerialize (esriSystem)	Provides access to members that XML serialize and deserialize an object to/from XML.
IXMLVersionSupport (esriSystem)	Provides access to members that help in serializing an object to different namespaces (versions).

Remarks

Use the UniqueValueRenderer to display feature data that falls into distinct categories based on attribute values. For example, if you have parcel data with land use types of residential, agriculture, and retail, you can use a different symbol to represent each unique land use type.

Each unique value can define a unique category, represented with a single symbol, or values can by combined by grouping so that more than one value is symbolized with the same symbol. Grouping is implemented by utilizing IUniqueValueRenderer::ReferenceValue. Also, headings can be used to organize categories in the table of contents and legend, see IUniqueValueRenderer::Heading.

Unique value renderering is typically based on a single attribute field, however up to 3 fields can be used. When more than one field is used, the combinations of the unique values from each field are used to define the categories. So, for example if two fields are used which store the values A and B; and X, Y, and Z respectively, then the initial categories will be defined as A|X, A|Y, A|Z, B|X, B|Y, and B|Z.