api:dk11:delphi:gisclassification.tgis_classificationvector
Table of Contents
TGIS_ClassificationVector class
DK11 for Delphi | GisClassification.TGIS_ClassificationVector | Classes | Constructors | Methods | Properties
Class that enables performing advanced vector data classification in the process of creating choropleth (thematic) maps.
Syntax
// Delphi type TGIS_ClassificationVector = class( TGIS_ClassificationAbstract ) end;
// C++ Builder class PASCALIMPLEMENTATION TGIS_ClassificationVector : public TGIS_ClassificationAbstract { };
Inheritance
Constructors
Methods
Inherited
Overrides
Protected
Private
| Name | Visibility | Description | |
|---|---|---|---|
| AddClassBreak | public | Adds a new class break. (Inherited from TGIS_ClassificationAbstract) |
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| Classify | public | Performs the classification. (Inherited from TGIS_ClassificationAbstract) |
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| Classify(TGIS_ParamsList) | public | Performs the classification and applies to defined ParamsList. (Inherited from TGIS_ClassificationAbstract) |
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| doCreate | protected | Internal constructor. (Inherited from TGIS_ClassificationAbstract) |
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| EstimateNumClasses | public | Performs the pre-classification and sets NumClasses property. (Inherited from TGIS_ClassificationAbstract) |
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| MustCalculateStatistics | public | If True, statistics from layer assigned to classification need to be calculated. (Inherited from TGIS_ClassificationAbstract) |
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Properties
Inherited
Protected
Private
| Name | Visibility | Description | |
|---|---|---|---|
| ClassBreaks | public | Computed class breaks. (Inherited from TGIS_ClassificationAbstract) |
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| ClassIdField | public | If not empty, the attribute field of the specified name will be populated with the class id values. | |
| ColorRamp | public | The color ramp that is used to assign colors for class breaks. (Inherited from TGIS_ClassificationAbstract) |
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| ColorRampName | public | The name of the built-in color ramp that is used to assign colors for class breaks. (Inherited from TGIS_ClassificationAbstract) |
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| EndColor | public | Ending color used to generate ramp for class breaks. (Inherited from TGIS_ClassificationAbstract) |
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| EndSize | public | Ending size or width for generating Params section; default is black. | |
| Field | public | Numeric field with values to be used in classification. | |
| ForceStatisticsCalculation | public | Forces the calculation of layer statistics. (Inherited from TGIS_ClassificationAbstract) |
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| Interval | public | Class interval size; default is 1. (Inherited from TGIS_ClassificationAbstract) |
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| Layer | public | Layer assigned to object. (Inherited from TGIS_ClassificationAbstract) |
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| Method | public | Classification method; NaturalBreaks by default. (Inherited from TGIS_ClassificationAbstract) |
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| NumClasses | public | Number of classes; default is 5, max is 30. (Inherited from TGIS_ClassificationAbstract) |
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| RenderType | public | Visual property which will be affected during classification. | |
| ShowLegend | public | If True, features will be shown in legend panel. (Inherited from TGIS_ClassificationAbstract) |
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| StartColor | public | Starting color used to generate ramp for class breaks. (Inherited from TGIS_ClassificationAbstract) |
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| StartSize | public | Starting size or width for generating Params section; default is white. | |
| Target | public | Indicates the data to be used for classification. (Inherited from TGIS_ClassificationAbstract) |
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Remarks
Example
Pseudocode:
// while 'lyr' is opened vector layer with added empty 'CLASS_ID' field classifier = new TGIS_Classification( lyr ); // select one of available classification methods classifier.Method = TGIS_ClassificationMethod.NaturalBreaks; // specify number of classes classifier.NumClasses = 5; // specify attribute field with numerical values classifier.Field = 'POPULATION'; // select visual property to be affected classifier.RenderType = TGIS_ClassificationRenderBy.Color; // write class ids to existing layer's field classifier.ClassIdField = 'CLASS_ID'; // check if layer's statistics require recalculation if classifier.MustCalculateStatistics then lyr.Statistics.Calculate ; // run classification process, visual properties will be applied automatically classifier.Classify ; // check generated class breaks values // class breaks count equals NumClasses + 1 for i from 0 to classifier.NumClasses value = classifier.ClassBreaks[i];
References
2024/05/31 20:42