编程实现Google Earth和ArcGIS的联动[demo]

    这个DEMO实现的功能就是在google earth中用鼠标获取地理坐标，然后自动定位到ARCGIS对应的区域影像中。前段时间因项目引导，在师兄的启发下，做了一个这样的Demo，后来因为各种原因一直没有进行下去。现在感觉还是有些用处的，现在抽空整理一下。
    Google Earth是一款优秀的Map Explorer，它的优秀在于使用普及和方便，虽然DigitalGlobe影像数据更新速度慢，但分辨率是还是很高的，最高可达到0.5m。如果忽略其误差，可以利用Google Earth的影像资源进行定位参考、解译参考、数字化等。
    Google Earth继Google Map API之后推出的Google Earth COM API ，提供的功能相对比较弱，一些功能据说似乎还存在着Bug。网址：http://earth.google.com/comapi/index.html。google earth的二次开发有两种方法：
（1）使用windows API控制两个进程的调用，利用google earth api实现核心功能。
（2）使用做好的务功能重点放在GE API开发上。
    这个demo使用的是GEVContorl(GEVC)，它是一个完全COM的控件,对截止目前所有版本的GoogleEarth都支持,具有很高的兼容性和可用性,能够将GE视图(地球视图)集成到开发人员的应用系统中,并且支持滚轮功能。下载地址：http://www.gis9.com/download.jsp
一、安装完GE后，系统会自动拷贝一个EARTHLib.dll，添加Google Earth 1.0 Type Library到库应用.
二、.NET中新建Arcgis command类。将生成一个dll，可以被ARCGIS自动添加到组件库中。
三、部分代码，主窗口中：

Imports EARTHLib
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Imports ESRI.ArcGIS.Controls
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Imports ESRI.ArcGIS.Geometry
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Imports ESRI.ArcGIS.Carto
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Imports ESRI.ArcGIS.SystemUI
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Imports ESRI.ArcGIS.ArcMapUI
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Imports ESRI.ArcGIS.esriSystem
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Imports ESRI.ArcGIS.Framework
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Imports ESRI.ArcGIS.Geodatabase
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Imports ESRI.ArcGIS.Display
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Imports System.Windows.Forms.Cursor
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Imports System.Drawing
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Imports System.Drawing.Drawing2D
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Public Class Form2
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Public g_GeHelper As EARTHLib.ApplicationGE 'GE的主应用API
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Public hookhelper As IHookHelper 'hookhelper
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Public longitude As Double '经度
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Public latitude As Double '维度
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Dim pApp As IApplication
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Dim pEnable As Boolean
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Dim pDoc As IMxDocument
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Dim pWorkspace As IWorkspace
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Dim pMap As IMap
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Dim pLayer As ILayer
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Dim pWorkE As IWorkspaceEdit
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Dim pFeaLayer As IFeatureLayer
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Private Structure POINTAPI
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Dim x As Double
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Dim y As Double
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End Structure
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Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
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'初始化应用GE
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g_GeHelper = New EARTHLib.ApplicationGE
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AxGEViewer1.HookGE(g_GeHelper.GetMainHwnd, g_GeHelper.GetRenderHwnd)
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End Sub
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Private Sub AxGEViewer1_MouseDownEvent(ByVal sender As System.Object, ByVal e As AxGEVControl.__GEViewer_MouseDownEvent) Handles AxGEViewer1.MouseDownEvent
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If CheckBox1.Checked = True Then
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Dim GePt As PointOnTerrainGE
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Dim pt As POINTAPI
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'屏幕坐标到GE屏幕坐标的转换
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pt.x = e.evtArgs.X * 2 / Me.Width - 1
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pt.y = -e.evtArgs.Y * 2 / Me.Height + 1
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'GE屏幕坐标到地理坐标的转换
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GePt = g_GeHelper.GetPointOnTerrainFromScreenCoords(CDbl(pt.X), CDbl(pt.Y))
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MsgBox("点击屏幕坐标：" & pt.x & " , " & pt.y & "获得ge坐标：" & GePt.Longitude & " , " & GePt.Latitude)
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longitude = GePt.Longitude
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latitude = GePt.Latitude
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pMap = hookhelper.ActiveView
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'arcmap中绘制点
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Dim point As IPoint
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point = New ESRI.ArcGIS.Geometry.Point
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point.PutCoords(longitude, latitude)
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Dim pMarkerElement As IMarkerElement
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pMarkerElement = New MarkerElement
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Dim pMarkerSymbol As ESRI.ArcGIS.Display.ISimpleMarkerSymbol
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pMarkerSymbol = New ESRI.ArcGIS.Display.SimpleMarkerSymbol
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pMarkerSymbol.Size = 3
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pMarkerSymbol.Style = ESRI.ArcGIS.Display.esriSimpleMarkerStyle.esriSMSDiamond
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Dim pElement As IElement
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pElement = pMarkerElement
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pElement.Geometry = point
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pMarkerElement.Symbol = pMarkerSymbol
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Dim pGraphicsContainer As IGraphicsContainer
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Dim pActiveView As IActiveView
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pActiveView = pMap
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'pActiveView.Extent.CenterAt(point)
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'arcmap中点的定位
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Dim pEnvelop As IEnvelope
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pEnvelop = pActiveView.Extent
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pEnvelop.CenterAt(point)
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pActiveView.Extent = pEnvelop
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pActiveView.Refresh()
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pGraphicsContainer = pMap
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pGraphicsContainer.AddElement(pMarkerElement, 0)
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pActiveView.PartialRefresh(esriViewDrawPhase.esriViewGraphics, Nothing, Nothing)
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End If
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End Sub
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Public WriteOnly Property hook() As IHookHelper
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Set(ByVal value As IHookHelper)
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hookhelper = value
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End Set
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End Property
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Private Sub Form2_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
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End Sub
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End Class

command.cs中实现组件注册：

Private m_hookHelper As IHookHelper
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' A creatable COM class must have a Public Sub New()
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' with no parameters, otherwise, the class will not be
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' registered in the COM registry and cannot be created
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' via CreateObject.
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Public Sub New()
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MyBase.New()
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' TODO: Define values for the public properties
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MyBase.m_category = "test" 'localizable text
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MyBase.m_caption = "tool1" 'localizable text
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MyBase.m_message = "This should work in ArcMap/MapControl/PageLayoutControl" 'localizable text
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MyBase.m_toolTip = "" 'localizable text
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MyBase.m_name = "" 'unique id, non-localizable (e.g. "MyCategory_MyCommand")
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Try
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'TODO: change bitmap name if necessary
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Dim bitmapResourceName As String = Me.GetType().Name + ".bmp"
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MyBase.m_bitmap = New Bitmap(Me.GetType(), bitmapResourceName)
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Catch ex As Exception
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System.Diagnostics.Trace.WriteLine(ex.Message, "Invalid Bitmap")
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End Try
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End Sub
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Public Overrides Sub OnCreate(ByVal hook As Object)
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If m_hookHelper Is Nothing Then m_hookHelper = New HookHelperClass
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If Not hook Is Nothing Then
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Try
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m_hookHelper.Hook = hook
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If m_hookHelper.ActiveView Is Nothing Then m_hookHelper = Nothing
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Catch
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m_hookHelper = Nothing
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End Try
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'Disable if hook fails
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If m_hookHelper Is Nothing Then
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MyBase.m_enabled = False
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Else
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MyBase.m_enabled = True
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End If
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'TODO: Add other initialization code
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End If
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End Sub
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Public Overrides Sub OnClick()
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'TODO: Add Command1.OnClick implementation
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Dim ce As IEnvelope = m_hookHelper.ActiveView.Extent
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ce.Expand(0.5, 0.5, True)
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m_hookHelper.ActiveView.Extent = ce
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m_hookHelper.ActiveView.Refresh()
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MsgBox("asdasd")
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Dim frm As Form2
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frm = New Form2
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frm.hookhelper = m_hookHelper
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frm.Show()
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End Sub
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End Class
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生成dll后，即可直接在arcmap中添加自定义的comand按钮进行调用了。