Multipart to single part feature

Multipart to single part feature

Explode

Link: http://edndoc.esri.com/arcobjects/8.3/?URL=/arcobjectsonline/samples/arcmap/explode/explode.htm

 

Created:	10/25/2000
Last Modified:	4/26/2002

Description:

This sample copies all feature in a selected feature class to a new feature class created in the same dataset. Features with multiple parts are broken up so that each part is saved as a new separate feature. 

How to use:

1. Select a feature layer in the table of contents.
2. Click the Explode command button.
3. Enter the name of the new feature class that will be created.
4. Once completed, add the new layer to ArcMap, notice all previous mutipart features are broken into separate features.

Application: ArcMap

Difficulty: Intermediate

Explode.cs

using System;

using System.Drawing;

using System.Windows.Forms;

using System.Runtime.InteropServices;

// Esri references

using ESRI.ArcObjects.Core;

using ESRI.ArcObjects.Samples.BaseClasses;

using ESRI.ArcObjects.Samples.CatIDs;

 

namespace ArcMapTools

{

/// <summary>

/// Explode breaks multi-part features in single part features.

/// </summary>

 

[ClassInterface(ClassInterfaceType.None)]

[GuidAttribute("689cebc3-b751-4919-a8c6-af59390371de")]

public sealed class ExplodeCS: BaseCommand

{

[ComRegisterFunction()]

static void Reg(String regKey)

{

MxCommand.Register(regKey);

}

 

[ComUnregisterFunction()]

static void Unreg(String regKey)

{

MxCommand.Unregister(regKey);

}

 

private IApplication m_app;

 

public ExplodeCS()

{

try

{

m_bitmap = new Bitmap(GetType().Assembly.GetManifestResourceStream("ArcMapTools.x.bmp"));

}

catch

{

m_bitmap = null;

}

m_category = "Developer Samples";

m_caption = "Explode Command (C#)";

m_message = "Converts parts to features in new feature class.";

m_toolTip = "Converts parts to features.";

m_name = "Explode";

}

 

public override void OnClick()

{

IMxDocument mxDoc = m_app.Document as IMxDocument;

// Make certain the selected item in the toc is a feature layer

if (mxDoc.SelectedItem == null)

{

MessageBox.Show("Select a feature layer in the table of contents " +

"as the input feature class.");

return;

}

 

if (!(mxDoc.SelectedItem is IFeatureLayer))

{

MessageBox.Show("No feature layer selected.");

return;

}

 

IFeatureLayer featureLayer = mxDoc.SelectedItem as IFeatureLayer;

IFeatureClass featureClass = featureLayer.FeatureClass;

 

// Don't process point layers, they have no multi-part features

if (featureClass.ShapeType == esriGeometryType.esriGeometryPoint)

{

MessageBox.Show("Point layers do not have multi-parts.");

return;

}

 

// Prompt for a new feature class name

FeatureClassDialog dlg = new FeatureClassDialog();

dlg.ShowDialog();

string name;

if (dlg.DialogResult == DialogResult.OK)

name = dlg.FileName;

else

return;

 

if (name == "") return;

 

try

{

// Create a new feature class to store the new features

// Create the feature class in the same dataset if one exists - shapefiles don't have one

IFields fields = featureLayer.FeatureClass.Fields;

IDataset dataset;

IFeatureWorkspace featureWorkspace;

IFeatureClass newFeatureClass;

if (featureClass.FeatureDataset == null)

{

dataset = featureClass as IDataset;

featureWorkspace = dataset.Workspace as IFeatureWorkspace;

newFeatureClass = featureWorkspace.CreateFeatureClass(name, fields, null, null,

esriFeatureType.esriFTSimple, featureClass.ShapeFieldName, "");

}

else

{

newFeatureClass = featureClass.FeatureDataset.CreateFeatureClass(name, fields, null, null,

esriFeatureType.esriFTSimple, featureClass.ShapeFieldName, "");

}

 

// Create an insert cursor

IFeatureCursor insertFeatureCursor = newFeatureClass.Insert(true);

IFeatureBuffer featureBuffer = newFeatureClass.CreateFeatureBuffer();

 

// Copy each feature from the original feature class to the new feature class

IFeatureCursor featureCursor = featureClass.Search(null, true);

IFeature feature;

IGeometryCollection geometryColl;

 

while ((feature = featureCursor.NextFeature()) != null)

{

geometryColl = feature.Shape as IGeometryCollection;

if (geometryColl.GeometryCount == 1)

{

InsertFeature(insertFeatureCursor, featureBuffer, feature, feature.Shape);

}

else if (feature.Shape.GeometryType == esriGeometryType.esriGeometryPolygon)

{

IPolygon2 polygon = feature.Shape as IPolygon2;

IPolygon[] polygonArray = new IPolygon[polygon.ExteriorRingCount];

polygon.GetConnectedComponents(polygon.ExteriorRingCount, polygonArray);

for (int i = 0; i <=polygon.ExteriorRingCount -1; i++)

{

InsertFeature(insertFeatureCursor, featureBuffer, feature, polygonArray[i]);

}

}

else

{

for (int i = 0; i <=geometryColl.GeometryCount -1; i++)

{

InsertFeature(insertFeatureCursor, featureBuffer, feature, geometryColl.get_Geometry(i));

}

}

}

}

catch

{

MessageBox.Show("An error occurred. Check that the shapefile specified doesn't already exist.");

}

}

 

public override void OnCreate(object hook)

{

m_app = hook as IApplication;

}

 

private void InsertFeature(IFeatureCursor featureCursor, IFeatureBuffer featureBuffer, IFeature originalFeature, IGeometry newShape)

{

IGeometryCollection newShapeColl = null;

IField field;

 

// Copy the attributes of the orig feature the new feature

IFields fields = originalFeature.Fields;

for (int i = 0; i <= fields.FieldCount - 1; i++)

{

field = fields.get_Field(i);

// skip OID and geometry

if (!(field.Type == esriFieldType.esriFieldTypeGeometry) &&

!(field.Type == esriFieldType.esriFieldTypeOID) && field.Editable)

{

featureBuffer.set_Value(i, originalFeature.get_Value(i));

}

}

 

// Handle cases where parts are passed down:

// InsertGeometries requires an IGeometry[] so we need to set up an array.

IGeometry[] geoArray = new IGeometry[1];

if (newShape.GeometryType == esriGeometryType.esriGeometryPath)

{

newShapeColl = new Polyline() as IGeometryCollection;

geoArray[0] = newShape;

newShapeColl.AddGeometries(1, geoArray);

newShape = newShapeColl as IGeometry;

}

else if (originalFeature.Shape.GeometryType == esriGeometryType.esriGeometryMultipoint)

{

if (newShape is IMultipoint)

{

IPointCollection pointColl = newShape as IPointCollection;

newShape = pointColl.get_Point(0);

}

geoArray[0] = newShape;

newShapeColl = new Multipoint() as IGeometryCollection;

newShapeColl.AddGeometries(1, geoArray);

newShape = newShapeColl as IGeometry;

}

 

featureBuffer.Shape = newShape;

featureCursor.InsertFeature(featureBuffer);

featureCursor.Flush();

}

}

}