ArcObjects Library Reference (System)

IClassify Interface

Provides access to members that control the classification methods.

Product Availability

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

Description

Classify objects apply one of several methods to statistically subdivide a set of numeric values into classes.

The IClassify interface is implemented by all the data classification objects (DefinedInterval, EqualInterval, NaturalBreaks, Quantile, StandardDeviation); this is the interface used to pass in histogram data and then classify it into breaks. The ClassID and MethodName properties are used by user interface dialog boxes to identify the classification object and establish what the classification is called.

In general, to classify a dataset, use this interface together with IClassBreaksRenderer. First, add data to the classification using SetHistogramData. Next, set the number of classes and generate breaks using Classify (typically use the same number of classes specified here for IClassBreaksRenderer.BreakCount). Then apply the classification to the renderer by cycling through ClassBreaks and setting each IClassBreaksRenderer.Break.

Members

		Description
	ClassBreaks	The array of class breaks (double). ClassBreaks(0) is the minimum value in the dataset, and subsequent breaks represent the upper limit of each class.
	ClassID	The CLSID for the classification object.
	Classify	Classifies data into the specified number of classes.
	MethodName	The name of the classification method (based on choice of classification object).
	SetHistogramData	Adds data in form of a histogram (array of values (doubles) and a paired array of frequencies (longs)) to the classification.

CoClasses that implement IClassify

CoClasses and Classes	Description
DefinedInterval	Defines a defined interval classification method.
EqualInterval	Defines an equal interval classification method.
GeometricalInterval	Defines a geometrical interval classification method.
NaturalBreaks	Defines a natural breaks classification method.
Quantile	Defines a quantile classification method.
StandardDeviation	Defines a standard deviation classification method.

Remarks

Do not call IClassify.Classify for a StandardDeviation classification until you have set deviation properties using IDeviationInterval.