How to work with the snap environment

SummaryThe snap environment manages snap agents and snap tolerance and is responsible for attempting to snap vertices and points using the snap environment settings. This topic includes code examples and methods to best manage snapping programmatically.

In this topic


Working with the snap environment

The ArcGIS Engine editor's snap environment (IEngineSnapEnvironment) controls each snap agent (IEngineSnapAgent), hit type settings, and snapping tolerance. The hit type of each feature snap agent is managed through the IEngineFeatureSnapAgent interface. All settings can be manually modified or verified on the Snapping Settings dialog box. See the following screen shot:

The ArcGIS Engine editor's snap environment also controls the snap tolerance. If required, you can provide an interface to allow the end user to manage the snap tolerance.
See the following code example to set up basic snap environment settings and turn on snap tips:

[C#]

publicvoid SnapEnvirSettings(IEngineEditor editor)
{
//Get the snap environment from the editor.
IEngineSnapEnvironment snapEnvironment = editor as IEngineSnapEnvironment; //Ensure there is a snap agent turned on in the snap environment.if (snapEnvironment.SnapAgentCount == 0)
{
System.Windows.Forms.MessageBox.Show(
"You need to turn on at least one snapping agent!!!");
return ;
} //Code to display the snap tolerance in a message box. double tolerance = snapEnvironment.SnapTolerance;
System.Windows.Forms.MessageBox.Show(Convert.ToString(tolerance)); //Set the snap tolerance.
snapEnvironment.SnapToleranceUnits =
esriEngineSnapToleranceUnits.esriEngineSnapToleranceMapUnits;
snapEnvironment.SnapTolerance = 15; //Turn on snap tips.
((IEngineEditProperties2)editor).SnapTips = true;
}

[VB.NET]

PublicSub SnapEnvirSettings(ByVal editor As IEngineEditor)
'Get the snap environment from the editor.Dim snapEnvironment As IEngineSnapEnvironment = editor As IEngineSnapEnvironment 'Ensure there is a snap agent turned on in the snap environment.If snapEnvironment.SnapAgentCount = 0 Then
System.Windows.Forms.MessageBox.Show("You need to turn on at least one snapping agent!!!")
ReturnEndIf'Code to display the snap tolerance in a message box.Dim tolerance AsDouble = snapEnvironment.SnapTolerance
System.Windows.Forms.MessageBox.Show(Convert.ToString(tolerance)) 'Set the snap tolerance.
snapEnvironment.SnapToleranceUnits = esriEngineSnapToleranceUnits.esriEngineSnapToleranceMapUnits
snapEnvironment.SnapTolerance = 15 'Turn on snap tips.
((IEngineEditProperties2)editor).SnapTips = TrueEndSub
This method checks the snap environment for selected snap agents. Feature snap agents are checked if the HitPartType is not equal to esriGeometryPartNone. The other snap agents are only registered if they are checked; therefore, if the number of snap agents is greater than the number of feature snap agents, a snap agent (sketch snap agent) is checked.
See the following code example:

[C#]

privatebool CheckIsAnySnapAgentSelected(IEngineSnapEnvironment snapEnvironment)
{
int snapAgentCount = snapEnvironment.SnapAgentCount;
int checkedFeatureSnapAgentCount = 0;
int featureSnapAgentCount = 0; //Loop through all registered snap agents in the snap environment. Count feature snap agents,//checked feature snap agents, and nonfeature snap agents.for (int i = 0; i < snapAgentCount; i++)
{
IEngineSnapAgent currentSnapAgent = snapEnvironment.get_SnapAgent(i);
if (currentSnapAgent is IEngineFeatureSnapAgent)
{
IEngineFeatureSnapAgent featureSnapAgent = currentSnapAgent as
IEngineFeatureSnapAgent;
featureSnapAgentCount++; //Determine if the feature snap agent is checked.if (featureSnapAgent.HitType !=
esriGeometryHitPartType.esriGeometryPartNone)
{
checkedFeatureSnapAgentCount++;
}
}
}
if (checkedFeatureSnapAgentCount > 0 || snapAgentCount > featureSnapAgentCount)
{
returntrue;
}
else
{
returnfalse;
}
}

[VB.NET]

PrivateFunction CheckIsAnySnapAgentSelected(ByVal snapEnvironment As IEngineSnapEnvironment) AsBooleanDim snapAgentCount AsInteger = snapEnvironment.SnapAgentCount
Dim checkedFeatureSnapAgentCount AsInteger = 0
Dim featureSnapAgentCount AsInteger = 0 'Loop through all registered snap agents in the snap environment. Count feature snap agents,'checked feature snap agents, and nonfeature snap agents.Dim i AsIntegerFor i = 0 To snapAgentCount - 1 Step i + 1
Dim currentSnapAgent As IEngineSnapAgent = snapEnvironment.get_SnapAgent(i)
IfTypeOf currentSnapAgent Is IEngineFeatureSnapAgent ThenDim featureSnapAgent As IEngineFeatureSnapAgent = currentSnapAgent As IEngineFeatureSnapAgent
featureSnapAgentCount = featureSnapAgentCount + 1 'Determine if the feature snap agent is checked.If featureSnapAgent.HitType <> esriGeomeTryHitPartType.esriGeomeTryPartNone Then
checkedFeatureSnapAgentCount = checkedFeatureSnapAgentCount + 1
EndIfEndIfNextIf checkedFeatureSnapAgentCount > 0 Or snapAgentCount > featureSnapAgentCount ThenReturnTrueElseReturnFalseEndIfEndFunction

Snap agents

Snap agents implement the IEngineSnapAgent interface and, when registered as a component category, are inserted into the ESRI snap agents component category. However, the feature snap agent (IEngineFeatureSnapAgent) is a more detailed class of snap agent, and each feature class has a feature snap agent instantiated when the snap environment window is first opened, if it hasn’t already been created programmatically.
See the following code example showing how to create a feature snap agent programmatically:

[C#]

publicvoid AddNewSnapAgent()
{
IEngineEditor editor = new EngineEditorClass();
IEngineEditLayers editLayers = editor as IEngineEditLayers;
IEngineSnapEnvironment snapEnvironment = editor as IEngineSnapEnvironment; //Check that the user is editing; otherwise, there will be no snap agent loaded.if (editLayers.TargetLayer == null)
{
System.Windows.Forms.MessageBox.Show("Please start an edit session");
return ;
} //Clear all existing snap agents.
snapEnvironment.ClearSnapAgents(); //Create a feature snap agent.
IEngineFeatureSnapAgent featureSnapAgent = new EngineFeatureSnap();
IFeatureClass layerFeatureClass = editLayers.TargetLayer.FeatureClass;
featureSnapAgent.FeatureClass = layerFeatureClass;
featureSnapAgent.HitType = esriGeometryHitPartType.esriGeometryPartBoundary; //Activate only the snap agent for the target layer.
snapEnvironment.AddSnapAgent(featureSnapAgent);
}

[VB.NET]

PublicSub AddNewSnapAgent()
Dim editor As IEngineEditor = New EngineEditorClass()
Dim editLayers As IEngineEditLayers = editor As IEngineEditLayers
Dim snapEnvironment As IEngineSnapEnvironment = editor As IEngineSnapEnvironment 'Check that the user is editing; otherwise, there will be no snap agent loaded.If editLayers.TargetLayer IsNothingThen
System.Windows.Forms.MessageBox.Show("Please start an edit session")
ReturnEndIf'Clear all existing snap agents.
snapEnvironment.ClearSnapAgents() 'Create a feature snap agent.Dim featureSnapAgent As IEngineFeatureSnapAgent = New EngineFeatureSnap()
Dim layerFeatureClass As IFeatureClass = editLayers.TargetLayer.FeatureClass
featureSnapAgent.FeatureClass = layerFeatureClass
featureSnapAgent.HitType = esriGeomeTryHitPartType.esriGeomeTryPartBoundary 'Activate only the snap agent for the target layer.
snapEnvironment.AddSnapAgent(featureSnapAgent)
EndSub
Programmatically changing the snap environment parameters does not require opening the snap window to change the settings. In ArcGIS Engine, the snap window reflects the snap environment settings while it is open. All IEngineSnapAgents, such as the edit sketch vertices snap agent, are visible on the snap window even if they have been programmatically removed; this allows the end user to turn them on and off as needed.

Snapping in z-dimension

ArcGIS Engine does not currently support snapping in z-dimension.

Snap point method

To use the SnapPoint method from the IEngineSnapEnvironment interface, an IPoint is passed to the method and used to find the closest feature to snap to. Using SnapPoint calls the IEngineSnapAgent.Snap method to then call each snap agent in priority order until it finds one that returns true. This results in new coordinates that are then assigned to the original point.
The order in which snap agents are added to the snap environment determines the priority of snap agents. This priority order is reflected in the snap environment window and can be changed using the window.

See Also:

IEngineEditProperties2.SnapTips Property

How to work with the snap environment的更多相关文章

  1. Ieditor

    Interfaces Description IActiveViewEvents (esriCarto) Provides access to events that occur when the s ...

  2. arcgis arcengine Using environment settings

    In this topic About using environment settings Environment settings summary table About using enviro ...

  3. 重新想象 Windows 8 Store Apps (56) - 系统 UI: Scale, Snap, Orientation, High Contrast 等

    [源码下载] 重新想象 Windows 8 Store Apps (56) - 系统 UI: Scale, Snap, Orientation, High Contrast 等 作者:webabcd ...

  4. 关于Ubuntu中snap安装软件太慢解决办法

    两种方法,一是下载好包手动安装,二设置snap的代理. 下载安装包方式 到 https://uappexplorer.com/snaps 搜索需要的 snap 包,然后下载 下载的时候选择对应的平台. ...

  5. deepin20使用snap并设置代理

    snap下载 $ sudo apt update $ sudo apt install snapd https://snapcraft.io/docs/installing-snap-on-ubunt ...

  6. OpenCloudOS使用snap安装.NET 6

    开源操作系统社区 OpenCloudOS 由腾讯与合作伙伴共同倡议发起,是完全中立.全面开放.安全稳定.高性能的操作系统及生态.OpenCloudOS 沉淀了多家厂商在软件和开源生态的优势,继承了腾讯 ...

  7. IEEE 802.11p (WAVE,Wireless Access in the Vehicular Environment)

    IEEE 802.11p(又称WAVE,Wireless Access in the Vehicular Environment)是一个由IEEE 802.11标准扩充的通讯协定.这个通讯协定主要用在 ...

  8. 修改/etc/profile和/etc/environment导致图形界面无法登陆的问题

    在使用ubuntu开发时,往往要修改PATH变量,有时会通过修改/etc/profile和/etc/environment来修改默认的PATH变量,但是一旦出错,很容易造成无法登陆进入图形界面的问题. ...

  9. System.Environment.CurrentDirectory和Application.StartupPath

    System.Environment.CurrentDirectory的含义是获取或设置当前工作路径,而Application.StartupPath是获取程序启动路径,表面上看二者没什么区别,但实际 ...

随机推荐

  1. mac安装brew 软件包管理工具Homebrew

    brew 全称Homebrew  是Mac OSX上的软件包管理工具 Homebrew 安装和卸载工具 只用一行命令就能完成 官方地址:    http://brew.sh/index.html   ...

  2. thuwc2019总结

    275,是我的自己的估分 而350,是面试线 就发挥而言,这次的发挥相当糟糕,第一天选择全场打暴力而不打签到题正解,第二天因A题思路想偏造成2h额外时间花费.第二题与第三题之间,我选择了难打的第三题而 ...

  3. 【BZOJ2082】【POI2010】Divine divisor 假的pollard-rho

    题目大意:给你$m$个数$a_i$,定义$n=\Pi_{i=1}^{m}a_i$.将$n$分解质因数为$\Pi p_i^{k_i} $,$p_i$是质数.请输出$2^{max(k_i)}-1$,以及存 ...

  4. POJ 1015

    #include<iostream> #include<algorithm> #define MAXN 201 #define count C_ount using names ...

  5. Numpy 创建数组2

    Numpy数组除了可以使用底层 ndarray 构造器来创建外,也可以同伙一下集中方式来创建. numpty.empty numpy.empty方法用来创建一个指定形状(shaoe).数据类型(dty ...

  6. Android 开发工具类 28_sendGETRequest

    以 GET 方式上传数据,小于 2K,且安全性要求不高的情况下. package com.wangjialin.internet.userInformation.service; import jav ...

  7. linux内核移植过程问题总结

    移植内核:2.6.30.4内核根目录下的.config为当前配置内核的且已经配置好的内核配置.make zImage以此为依据配置内核的过程:cd linux-2.6.30.4(进入Linux根目录) ...

  8. 11 - JavaSE之GUI

    GUI(念法 gu yi) AWT AWT(Abstract Window Toolkit 抽象窗口开发包,在C# 或者 linux窗口开发类之上又封装一层,达到跨平台的目的)包括了很多类和接口,用于 ...

  9. Innosetup新增Wizard Page

    Innosetup 新增一个向导页面,让用户选择安装方式 转载于:http://www.docin.com/p-612536939.html 在Innosetup的向导页面中,新增一个页面,提供两种安 ...

  10. mysql RR下不存在则插入

    主要看并发事务中不存在则插入(只有key索引)的阻塞情况. 表定义: mysql> desc user; +-------------+------------------+------+--- ...