1、前言
前面一篇博客介绍了如何按距离或按比例将1条线段分成2条线段的方法，核心就是利用IFeatureEdit接口的Split方法进行分割。但就像之前说的，该方法只适用于将1条线段分成2条线段，如果我们希望将1条线段分成n条线段（n >= 2），那又该怎么做呢？下面开始介绍。
2、获取分割点
假设有一条长度为100米的线段，现在按照30米的距离间隔对其进行分割，那么就会得到如下图所示的结果，线段被A、B、C三个分割点分成了4份，
现在第一个问题来了：如何获取这些分割点？其实这个问题很简单，在IPolyline接口中有一个QueryPoint方法，该方法可以在指定的距离处获取线上的一点，我们可以来测试一下：
获取分割点代码
using ESRI.ArcGIS.ADF.BaseClasses;
using ESRI.ArcGIS.ADF.CATIDs;
using ESRI.ArcGIS.Carto;
using ESRI.ArcGIS.Controls;
using ESRI.ArcGIS.Display;
using ESRI.ArcGIS.esriSystem;
using ESRI.ArcGIS.Geodatabase;
using ESRI.ArcGIS.Geometry;
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Runtime.InteropServices;
using System.Windows.Forms;
namespace WindowsFormsApplication1.Command
{
/// <summary>
/// Summary description for SplitByDistanceCommand.
/// </summary>
[Guid("b8a71064-25d0-4816-9b9a-0f3738ddf981")]
[ClassInterface(ClassInterfaceType.None)]
[ProgId("WindowsFormsApplication1.Command.SplitByDistanceCommand")]
public sealed class SplitByDistanceCommand : BaseCommand
{
#region COM Registration Function(s)
[ComRegisterFunction()]
[ComVisible(false)]
static void RegisterFunction(Type registerType)
{
// Required for ArcGIS Component Category Registrar support
ArcGISCategoryRegistration(registerType);
//
// TODO: Add any COM registration code here
//
}
[ComUnregisterFunction()]
[ComVisible(false)]
static void UnregisterFunction(Type registerType)
{
// Required for ArcGIS Component Category Registrar support
ArcGISCategoryUnregistration(registerType);
//
// TODO: Add any COM unregistration code here
//
}
#region ArcGIS Component Category Registrar generated code
/// <summary>
/// Required method for ArcGIS Component Category registration -
/// Do not modify the contents of this method with the code editor.
/// </summary>
private static void ArcGISCategoryRegistration(Type registerType)
{
string regKey = string.Format("HKEY_CLASSES_ROOT\\CLSID\\{{{0}}}", registerType.GUID);
ControlsCommands.Register(regKey);
}
/// <summary>
/// Required method for ArcGIS Component Category unregistration -
/// Do not modify the contents of this method with the code editor.
/// </summary>
private static void ArcGISCategoryUnregistration(Type registerType)
{
string regKey = string.Format("HKEY_CLASSES_ROOT\\CLSID\\{{{0}}}", registerType.GUID);
ControlsCommands.Unregister(regKey);
}
#endregion
#endregion
private IHookHelper m_hookHelper;
public SplitByDistanceCommand()
{
//
// TODO: Define values for the public properties
//
base.m_category = ""; //localizable text
base.m_caption = ""; //localizable text
base.m_message = ""; //localizable text
base.m_toolTip = ""; //localizable text
base.m_name = ""; //unique id, non-localizable (e.g. "MyCategory_MyCommand")
try
{
//
// TODO: change bitmap name if necessary
//
string bitmapResourceName = GetType().Name + ".bmp";
base.m_bitmap = new Bitmap(GetType(), bitmapResourceName);
}
catch (Exception ex)
{
System.Diagnostics.Trace.WriteLine(ex.Message, "Invalid Bitmap");
}
}
#region Overridden Class Methods
/// <summary>
/// Occurs when this command is created
/// </summary>
/// <param name="hook">Instance of the application</param>
public override void OnCreate(object hook)
{
if (hook == null)
return;
if (m_hookHelper == null)
m_hookHelper = new HookHelperClass();
m_hookHelper.Hook = hook;
// TODO: Add other initialization code
}
/// <summary>
/// Occurs when this command is clicked
/// </summary>
public override void OnClick()
{
if (m_hookHelper.FocusMap.SelectionCount != 1)
{
MessageBox.Show("请选择1条线要素进行分割", "提示", MessageBoxButtons.OK, MessageBoxIcon.Warning);
return;
}
// 获取被选择的要素
IEnumFeature pEnumFeature = m_hookHelper.FocusMap.FeatureSelection as IEnumFeature;
pEnumFeature.Reset();
IFeature pFeature = pEnumFeature.Next();
if (pFeature.Shape is IPoint || pFeature.Shape is IPolygon)
{
MessageBox.Show("请选择1条线要素进行分割", "提示", MessageBoxButtons.OK, MessageBoxIcon.Warning);
return;
}
// 获取分割点
IPolyline pPolyline = pFeature.ShapeCopy as IPolyline;
List<IPoint> points = new List<IPoint>();
double distance = 50;
double interval = 50;
while (distance < pPolyline.Length)
{
IPoint pPoint = new ESRI.ArcGIS.Geometry.Point();
pPolyline.QueryPoint(esriSegmentExtension.esriNoExtension, distance, false, pPoint);
points.Add(pPoint);
distance += interval;
}
// 创建颜色
IRgbColor pRgbColor = new RgbColor();
pRgbColor.Red = 255;
pRgbColor.Green = 0;
pRgbColor.Blue = 0;
// 创建点符号
ISimpleMarkerSymbol pSimpleMarkerSymbol = new SimpleMarkerSymbol();
pSimpleMarkerSymbol.Color = pRgbColor;
pSimpleMarkerSymbol.Size = 15;
pSimpleMarkerSymbol.Style = esriSimpleMarkerStyle.esriSMSCircle;
// 绘制分割点
foreach (IPoint pPoint in points)
{
IMarkerElement pMarkerElement = new MarkerElement() as IMarkerElement;
pMarkerElement.Symbol = pSimpleMarkerSymbol;
IElement pElement = pMarkerElement as IElement;
pElement.Geometry = pPoint;
m_hookHelper.ActiveView.GraphicsContainer.AddElement(pElement, 0);
}
// 刷新地图
m_hookHelper.ActiveView.Refresh();
}
#endregion
}
}
运行结果如下图所示，可以发现：这条线段长度为164米，按照50米的距离间隔对其进行分割，结果在50米、100米、150米处产生了3个分割点。
3、分割操作的结束条件
现在需要思考一下：分割操作的结束条件是什么？还是上面的情景，我们来模拟一下：
- 获取长度为
164米的线段，在50米处执行分割操作，得到50米和114米两条线段 - 获取长度为
114米的线段，在50米处执行分割操作，得到50米和64米两条线段 - 获取长度为
64米的线段，在50米处执行分割操作，得到50米和14米两条线段 - 由于
50米和14米这两条线段的长度均小于等于50米，因此不再执行分割操作。
通过上面的分析可以得出结论：
每次分割的对象都是距离较长的那条线段当执行分割操作后的两条线段长度均小于等于指定的距离间隔时，分割结束
4、距离分割
4.1、主界面代码
using ESRI.ArcGIS.Controls;
using ESRI.ArcGIS.SystemUI;
using System;
using System.Windows.Forms;
using WindowsFormsApplication1.Command;
namespace WindowsFormsApplication1
{
public partial class MainForm : Form
{
public MainForm()
{
InitializeComponent();
axMapControl1.LoadMxFile(@"C:\Users\DSF\Desktop\data\无标题.mxd");
axMapControl1.Extent = axMapControl1.FullExtent;
btnStartEditing.Enabled = true;
btnStopEditing.Enabled = false;
btnSelect.Enabled = false;
btnSplitByDistance.Enabled = false;
btnSplitByRatio.Enabled = false;
}
// 开始编辑
private void btnStartEditing_Click(object sender, EventArgs e)
{
ICommand command = new ControlsEditingStartCommand();
command.OnCreate(axMapControl1.Object);
command.OnClick();
btnStartEditing.Enabled = false;
btnStopEditing.Enabled = true;
btnSelect.Enabled = true;
btnSplitByDistance.Enabled = true;
btnSplitByRatio.Enabled = true;
}
// 结束编辑
private void btnStopEditing_Click(object sender, EventArgs e)
{
ICommand saveCommand = new ControlsEditingSaveCommand();
saveCommand.OnCreate(axMapControl1.Object);
saveCommand.OnClick();
ICommand clearSelectionCommand = new ControlsClearSelectionCommand();
clearSelectionCommand.OnCreate(axMapControl1.Object);
clearSelectionCommand.OnClick();
btnStartEditing.Enabled = true;
btnStopEditing.Enabled = false;
btnSelect.Enabled = false;
btnSplitByDistance.Enabled = false;
btnSplitByRatio.Enabled = false;
}
// 选择要素
private void btnSelect_Click(object sender, EventArgs e)
{
ICommand command = new ControlsSelectFeaturesTool();
command.OnCreate(axMapControl1.Object);
axMapControl1.CurrentTool = command as ITool;
}
// 距离分割
private void btnSplitByDistance_Click(object sender, EventArgs e)
{
ICommand command = new SplitByDistanceCommand();
command.OnCreate(axMapControl1.Object);
command.OnClick();
}
// 比例分割
private void btnSplitByRatio_Click(object sender, EventArgs e)
{
ICommand command = new SplitByRatioCommand();
command.OnCreate(axMapControl1.Object);
command.OnClick();
}
}
}
4.2、距离分割代码
using ESRI.ArcGIS.ADF.BaseClasses;
using ESRI.ArcGIS.ADF.CATIDs;
using ESRI.ArcGIS.Controls;
using ESRI.ArcGIS.esriSystem;
using ESRI.ArcGIS.Geodatabase;
using ESRI.ArcGIS.Geometry;
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Runtime.InteropServices;
using System.Windows.Forms;
namespace WindowsFormsApplication1.Command
{
/// <summary>
/// Summary description for SplitByDistanceCommand.
/// </summary>
[Guid("b8a71064-25d0-4816-9b9a-0f3738ddf981")]
[ClassInterface(ClassInterfaceType.None)]
[ProgId("WindowsFormsApplication1.Command.SplitByDistanceCommand")]
public sealed class SplitByDistanceCommand : BaseCommand
{
#region COM Registration Function(s)
[ComRegisterFunction()]
[ComVisible(false)]
static void RegisterFunction(Type registerType)
{
// Required for ArcGIS Component Category Registrar support
ArcGISCategoryRegistration(registerType);
//
// TODO: Add any COM registration code here
//
}
[ComUnregisterFunction()]
[ComVisible(false)]
static void UnregisterFunction(Type registerType)
{
// Required for ArcGIS Component Category Registrar support
ArcGISCategoryUnregistration(registerType);
//
// TODO: Add any COM unregistration code here
//
}
#region ArcGIS Component Category Registrar generated code
/// <summary>
/// Required method for ArcGIS Component Category registration -
/// Do not modify the contents of this method with the code editor.
/// </summary>
private static void ArcGISCategoryRegistration(Type registerType)
{
string regKey = string.Format("HKEY_CLASSES_ROOT\\CLSID\\{{{0}}}", registerType.GUID);
ControlsCommands.Register(regKey);
}
/// <summary>
/// Required method for ArcGIS Component Category unregistration -
/// Do not modify the contents of this method with the code editor.
/// </summary>
private static void ArcGISCategoryUnregistration(Type registerType)
{
string regKey = string.Format("HKEY_CLASSES_ROOT\\CLSID\\{{{0}}}", registerType.GUID);
ControlsCommands.Unregister(regKey);
}
#endregion
#endregion
private IHookHelper m_hookHelper;
public SplitByDistanceCommand()
{
//
// TODO: Define values for the public properties
//
base.m_category = ""; //localizable text
base.m_caption = ""; //localizable text
base.m_message = ""; //localizable text
base.m_toolTip = ""; //localizable text
base.m_name = ""; //unique id, non-localizable (e.g. "MyCategory_MyCommand")
try
{
//
// TODO: change bitmap name if necessary
//
string bitmapResourceName = GetType().Name + ".bmp";
base.m_bitmap = new Bitmap(GetType(), bitmapResourceName);
}
catch (Exception ex)
{
System.Diagnostics.Trace.WriteLine(ex.Message, "Invalid Bitmap");
}
}
#region Overridden Class Methods
/// <summary>
/// Occurs when this command is created
/// </summary>
/// <param name="hook">Instance of the application</param>
public override void OnCreate(object hook)
{
if (hook == null)
return;
if (m_hookHelper == null)
m_hookHelper = new HookHelperClass();
m_hookHelper.Hook = hook;
// TODO: Add other initialization code
}
/// <summary>
/// Occurs when this command is clicked
/// </summary>
public override void OnClick()
{
if (m_hookHelper.FocusMap.SelectionCount != 1)
{
MessageBox.Show("请选择1条线要素进行分割", "提示", MessageBoxButtons.OK, MessageBoxIcon.Warning);
return;
}
// 获取被选择的要素
IEnumFeature pEnumFeature = m_hookHelper.FocusMap.FeatureSelection as IEnumFeature;
pEnumFeature.Reset();
IFeature pFeature = pEnumFeature.Next();
if (pFeature.Shape is IPoint || pFeature.Shape is IPolygon)
{
MessageBox.Show("请选择1条线要素进行分割", "提示", MessageBoxButtons.OK, MessageBoxIcon.Warning);
return;
}
// 获取分割点
IPolyline pPolyline = pFeature.ShapeCopy as IPolyline;
List<IPoint> points = new List<IPoint>();
double distance = 50;
double interval = 50;
while (distance < pPolyline.Length)
{
IPoint pPoint = new ESRI.ArcGIS.Geometry.Point();
pPolyline.QueryPoint(esriSegmentExtension.esriNoExtension, distance, false, pPoint);
points.Add(pPoint);
distance += interval;
}
// 分割线要素
foreach (IPoint pPoint in points)
{
IFeatureEdit pFeatureEdit = pFeature as IFeatureEdit;
ISet pSet = pFeatureEdit.Split(pPoint);
pSet.Reset();
pFeature = GetFeatureByDistance(pSet);
}
// 刷新地图
m_hookHelper.ActiveView.Refresh();
}
// 获取Set中距离较长的线要素
private IFeature GetFeatureByDistance(ISet pSet)
{
IFeature pFirstFeature = pSet.Next() as IFeature;
IFeature pSecondFeature = pSet.Next() as IFeature;
IPolyline pFirstPolyline = pFirstFeature.ShapeCopy as IPolyline;
IPolyline pSecondPolyline = pSecondFeature.ShapeCopy as IPolyline;
return pFirstPolyline.Length <= pSecondPolyline.Length ? pSecondFeature : pFirstFeature;
}
#endregion
}
}
运行结果如下图所示：
5、比例分割
比例分割如下图所示：
其实和按距离分割的逻辑差不多，唯一的区别就是在获取分割点时改为按比例获取，其代码如下：
using ESRI.ArcGIS.ADF.BaseClasses;
using ESRI.ArcGIS.ADF.CATIDs;
using ESRI.ArcGIS.Controls;
using ESRI.ArcGIS.esriSystem;
using ESRI.ArcGIS.Geodatabase;
using ESRI.ArcGIS.Geometry;
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Runtime.InteropServices;
using System.Windows.Forms;
namespace WindowsFormsApplication1.Command
{
/// <summary>
/// Summary description for SplitByRatioCommand.
/// </summary>
[Guid("d4624838-4abc-458e-b6cf-fb5d78562e96")]
[ClassInterface(ClassInterfaceType.None)]
[ProgId("WindowsFormsApplication1.Command.SplitByRatioCommand")]
public sealed class SplitByRatioCommand : BaseCommand
{
#region COM Registration Function(s)
[ComRegisterFunction()]
[ComVisible(false)]
static void RegisterFunction(Type registerType)
{
// Required for ArcGIS Component Category Registrar support
ArcGISCategoryRegistration(registerType);
//
// TODO: Add any COM registration code here
//
}
[ComUnregisterFunction()]
[ComVisible(false)]
static void UnregisterFunction(Type registerType)
{
// Required for ArcGIS Component Category Registrar support
ArcGISCategoryUnregistration(registerType);
//
// TODO: Add any COM unregistration code here
//
}
#region ArcGIS Component Category Registrar generated code
/// <summary>
/// Required method for ArcGIS Component Category registration -
/// Do not modify the contents of this method with the code editor.
/// </summary>
private static void ArcGISCategoryRegistration(Type registerType)
{
string regKey = string.Format("HKEY_CLASSES_ROOT\\CLSID\\{{{0}}}", registerType.GUID);
ControlsCommands.Register(regKey);
}
/// <summary>
/// Required method for ArcGIS Component Category unregistration -
/// Do not modify the contents of this method with the code editor.
/// </summary>
private static void ArcGISCategoryUnregistration(Type registerType)
{
string regKey = string.Format("HKEY_CLASSES_ROOT\\CLSID\\{{{0}}}", registerType.GUID);
ControlsCommands.Unregister(regKey);
}
#endregion
#endregion
private IHookHelper m_hookHelper;
public SplitByRatioCommand()
{
//
// TODO: Define values for the public properties
//
base.m_category = ""; //localizable text
base.m_caption = ""; //localizable text
base.m_message = ""; //localizable text
base.m_toolTip = ""; //localizable text
base.m_name = ""; //unique id, non-localizable (e.g. "MyCategory_MyCommand")
try
{
//
// TODO: change bitmap name if necessary
//
string bitmapResourceName = GetType().Name + ".bmp";
base.m_bitmap = new Bitmap(GetType(), bitmapResourceName);
}
catch (Exception ex)
{
System.Diagnostics.Trace.WriteLine(ex.Message, "Invalid Bitmap");
}
}
#region Overridden Class Methods
/// <summary>
/// Occurs when this command is created
/// </summary>
/// <param name="hook">Instance of the application</param>
public override void OnCreate(object hook)
{
if (hook == null)
return;
if (m_hookHelper == null)
m_hookHelper = new HookHelperClass();
m_hookHelper.Hook = hook;
}
/// <summary>
/// Occurs when this command is clicked
/// </summary>
public override void OnClick()
{
if (m_hookHelper.FocusMap.SelectionCount != 1)
{
MessageBox.Show("请选择1条线要素进行分割", "提示", MessageBoxButtons.OK, MessageBoxIcon.Warning);
return;
}
// 获取被选择的要素
IEnumFeature pEnumFeature = m_hookHelper.FocusMap.FeatureSelection as IEnumFeature;
pEnumFeature.Reset();
IFeature pFeature = pEnumFeature.Next();
if (pFeature.Shape is IPoint || pFeature.Shape is IPolygon)
{
MessageBox.Show("请选择1条线要素进行分割", "提示", MessageBoxButtons.OK, MessageBoxIcon.Warning);
return;
}
// 获取分割点
IPolyline pPolyline = pFeature.ShapeCopy as IPolyline;
List<IPoint> points = new List<IPoint>();
double ratio = 0.2;
double interval = 0.2;
while (ratio < 1)
{
IPoint pPoint = new ESRI.ArcGIS.Geometry.Point();
pPolyline.QueryPoint(esriSegmentExtension.esriNoExtension, ratio, true, pPoint);
points.Add(pPoint);
ratio += interval;
}
// 分割线要素
foreach (IPoint pPoint in points)
{
IFeatureEdit pFeatureEdit = pFeature as IFeatureEdit;
ISet pSet = pFeatureEdit.Split(pPoint);
pSet.Reset();
pFeature = GetFeatureByDistance(pSet);
}
// 刷新地图
m_hookHelper.ActiveView.Refresh();
}
// 获取Set中距离较长的线要素
private IFeature GetFeatureByDistance(ISet pSet)
{
IFeature pFirstFeature = pSet.Next() as IFeature;
IFeature pSecondFeature = pSet.Next() as IFeature;
IPolyline pFirstPolyline = pFirstFeature.ShapeCopy as IPolyline;
IPolyline pSecondPolyline = pSecondFeature.ShapeCopy as IPolyline;
return pFirstPolyline.Length <= pSecondPolyline.Length ? pSecondFeature : pFirstFeature;
}
#endregion
}
}
运行结果如下图所示：
如果你想实现：对一条线段进行等比例分割，那么只需要修改一下分割比例即可。比如对1条线段5等分只需要将分割比例设置为0.2即可：
double ratio = 0.2;
double interval = 0.2;
运行结果如下图所示：