google earth二次开发的功能非常弱，资料也非常少。
下面给出两个链接：
GoogleEarth API使用说明
link：http://www.tootc.cn/bbs/viewthread.php?tid=2602
abstract：
GoogleEarth API Keyhole 1.0 Type Library
当你要使用GoogleEarth API时首先要在工程里引用他，以VB为例，在“工程”菜单中选择“引用”，
如果你已经安装了GoogleEarth，那么引用栏里会有“Keyhole 1.0 Type Library ”
而它是定位于GoogleEarth的主程序的。
引用完毕后，打开对象浏览器，你就可以看到GoogleEarth API的类和函数及属性了！！
GoogleEarth API有4个类，每个类下面有多个函数及属性
下面将我常用的函数的说明写到下面：
Class KHFeature
Property hasView As Long 只读 暂时还不知道什么意思，没用过，哪位高手能给个解释
Property visibility As Long 地标的可视选项
Class KHInterface
Property autopilotSpeed As Double GE的自动飞行速度
Function currentView(terrain As Long) As KHViewInfo GE的当前视图
Property currentViewExtents As KHViewExtents 只读
Function getFeatureByName(name As String) As KHFeature
Function getPointOnTerrainFromScreenCoords(screen_x As Double, screen_y As Double) As Double()
Sub LoadKml(kmlData As String) 导入KML字符串,不支持中文
Sub OpenFile(fileName As String) 打开地标文件
Sub QuitApplication() 退出程序
Sub SaveScreenShot(fileName As String, quality As Long) 保存截图
Sub setFeatureView(feature As KHFeature, speed As Double)
Sub SetRenderWindowSize(width As Long, height As Long)
Sub setView(view As KHViewInfo, terrain As Long, speed As Double) 用KHViewInfo设置视角范围
Sub setViewParams(lat As Double, lon As Double, range As Double, _
tilt As Double, azimuth As Double, terrain As Long, speed As Double)用数值设置视角范围
Property streamingProgressPercentage As Long 只读 数据传输进度百分比
Class KHViewExtents
property east As Double 只读
Property north As Double 只读
Property south As Double 只读
Property west As Double 只读
Class KHViewInfo
Property azimuth As Double 方位角
Property latitude As Double 纬度
Property longitude As Double 经度
Property range As Double 范围
Property tilt As Double 倾角
利用这些函数，可以对GE进行部分 控制，实现一些小的功能，
Google Earth COM API Documentation
link：http://earth.google.com/comapi/index.html
Introduction
This document describes the features of the Google Earth COM API. The Google Earth COM API allows third party applications to query information from and send commands to Google Earth. Through IApplicationGE, applications can query the current viewport, control the 3D viewpoint, use KML features, and more.
This Google Earth COM API documentation package includes:
- This documentation
- earth.idl - the original IDL for COM interface and documentation
GEVContorl(GEVC)是一个完全COM的控件
GEVContorl(GEVC)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.通过GEVC开发人员就可以不用关心GE如何集成到系统中,把工作重心直接放在利用GE API开发业务功能上.
link: http://www.gis9.com