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Embedding Google Earth in a C# Application

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8 Dec 2008LGPL32 min read 350.7K   137   97
How to embed the Google Earth scene in a C# application.

Introduction

If you're interested in utilizing the Google Earth viewer as a control in a custom application, then continue reading. There are quite a few links around the Internet that provide information as to how to add references to your project, create a ApplicationGE, and control the Google Earth application. However, most of these tutorials do not focus on the details of embedding Google Earth in an application. That's what I will focus on here. From now on, GE means Google Earth.

The Code

You'll probably start off on your embedding adventure much like I did, with:

C#
EARTHLib.ApplicationGE ge = new ApplicationGEClass();

If the GE process already exists, we will obtain a reference to it; if not, a new process will be created, and you would see the GE logo flash on the screen while loading. You will then see the main Google Earth screen with the embedded viewer. Since we are interested in embedding GE, we are not interested in having the main screen around, so we hide it!

C#
ShowWindowAsync(ge.GetMainHwnd(), 0);

For all intensive purposes, we now have an empty screen. What we'd like to do next is embed the scene that GE renders into our application. We accomplish this by setting the render Hwnds parent to that of the window we would like to render to:

C#
SetParent(ge.GetRenderHwnd(), this.Handle.ToInt32());

In the example above, 'this' is a Windows Form. The end result, if you perform these same steps, should look similar to the image below, although I do warn that results may vary :-)

google_earth_embedded.jpg

You will notice that resizing the window has no effect on the scene. If you plan on embedding GE in an application for any useful purposes, you'll most likely need it to respond to resizing. I spent a bit of time sniffing into the events that were passed to the scene when I performed re-size of the main GE application window. This led me to a special event, WM_QT_PAINT, in addition to a sequence of others. It took a bit of tinkering to get it all right, but this appeared to work for me:

C#
SendMessage(ge.GetMainHwnd(), WM_COMMAND, WM_PAINT, 0);
PostMessage(ge.GetMainHwnd(), WM_QT_PAINT, 0, 0);
SetWindowPos( ge.GetMainHwnd(), HWND_TOP, 0, 0, (int)this.Width, 
             (int)this.Height, SWP_FRAMECHANGED);
SendMessage(ge.GetRenderHwnd(), WM_COMMAND, WM_SIZE, 0);

This should allow the scene to adjust according to the parent form's size. I bundled this up into a method named "ResizeGoogleControl", and called it after SetParent and within my Form_Resize event. The results are illustrated in this image:

google_earth_embedded_good.jpg

The Example

I slapped together a test app that you are welcome to use for reference. If you have any comments or suggestions, be sure to send me an email or add a comment. Create a new C# project in Visual Studio and replace the Form1.cs code with this:

C#
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Runtime.InteropServices;
using System.Text;
using System.Windows.Forms;

using EARTHLib;

namespace resize_google_earth
{

public partial class Form1 : Form
{
    [DllImport("user32.dll")]
    private static extern int SetParent(
    int hWndChild,
    int hWndParent);

    [DllImport("user32.dll")]
    private static extern bool ShowWindowAsync(
    int hWnd,
    int nCmdShow);

    [DllImport("user32.dll", SetLastError = true)]
    private static extern bool PostMessage(
    int hWnd,
    uint Msg,
    int wParam,
    int lParam);

    [DllImport("user32.dll", EntryPoint = "SetWindowPos")]
    private static extern bool SetWindowPos(
    int hWnd,
    int hWndInsertAfter,
    int X,
    int Y,
    int cx,
    int cy,
    uint uFlags);

    [DllImport("user32.dll")]
    private static extern int SendMessage(
    int hWnd,
    uint Msg,
    int wParam,
    int lParam);

    private const int HWND_TOP = 0x0;
    private const int WM_COMMAND = 0x0112;
    private const int WM_QT_PAINT = 0xC2DC;
    private const int WM_PAINT = 0x000F;
    private const int WM_SIZE = 0x0005;
    private const int SWP_FRAMECHANGED = 0x0020;

    public Form1()
    {
        InitializeComponent();

        ge = new ApplicationGEClass();

        ShowWindowAsync(ge.GetMainHwnd(), 0);
        SetParent(ge.GetRenderHwnd(), this.Handle.ToInt32());
        ResizeGoogleControl();
    }

    private void Form1_Resize(object sender, EventArgs e)
    {
        ResizeGoogleControl();
    }

    private void ResizeGoogleControl()
    {
        SendMessage(ge.GetMainHwnd(), WM_COMMAND, WM_PAINT, 0);
        PostMessage(ge.GetMainHwnd(), WM_QT_PAINT, 0, 0);

        SetWindowPos(
        ge.GetMainHwnd(),
        HWND_TOP,
        0,
        0,
        (int)this.Width,
        (int)this.Height,
        SWP_FRAMECHANGED);

        SendMessage(ge.GetRenderHwnd(), WM_COMMAND, WM_SIZE, 0);
    }

    private EARTHLib.ApplicationGE ge = null;
}
}

License

This article, along with any associated source code and files, is licensed under The GNU Lesser General Public License (LGPLv3)


Written By
Software Developer
United States United States
I love to write programs and vim is my editor of choice. Programming languages fascinate me and I feel at least reasonably familiar with C, python, C++, JAVA, C#, ECMAScript, Lua and Ruby. I also use a few open source relational database systems; postgresql, mysql, sqlite. Some of my interests include: programming languages, geoprocessing, number theory, network protocols, web services, cryptography, linux, windows, open source, GIS.

See: http://www.joevial.com

Comments and Discussions

 
QuestionWhere to find more? Pin
meridbt24-Mar-15 23:48
meridbt24-Mar-15 23:48 
QuestionThank you!!! Pin
eugenia monfort16-Dec-14 2:02
eugenia monfort16-Dec-14 2:02 
QuestionI have two errors while building your code. Both in string "ge = new ApplicationGEClass();": 1. Error 1 The type 'EARTHLib.ApplicationGEClass' has no constructors defined 2. Error 2 Interop type 'EARTHLib.ApplicationGEClass' cannot be embedded. Us Pin
hknern14-Dec-14 23:17
hknern14-Dec-14 23:17 
AnswerRe: I have two errors while building your code. Both in string "ge = new ApplicationGEClass();": 1. Error 1 The type 'EARTHLib.ApplicationGEClass' has no constructors defined 2. Error 2 Interop type 'EARTHLib.ApplicationGEClass' cannot be embedded Pin
meridbt23-Mar-15 23:57
meridbt23-Mar-15 23:57 
GeneralRe: I have two errors while building your code. Both in string "ge = new ApplicationGEClass();": 1. Error 1 The type 'EARTHLib.ApplicationGEClass' has no constructors defined 2. Error 2 Interop type 'EARTHLib.ApplicationGEClass' cannot be embedded Pin
alrajhi2013-Nov-17 6:43
alrajhi2013-Nov-17 6:43 
QuestionSome Questions Pin
Mollaahmadi8-Sep-14 19:49
Mollaahmadi8-Sep-14 19:49 
BugGoogleEarth process isn't closed after form closing! Pin
Member 1088091513-Jun-14 2:11
Member 1088091513-Jun-14 2:11 
GeneralRe: GoogleEarth process isn't closed after form closing! Pin
Zibusiso22-Aug-14 2:31
professionalZibusiso22-Aug-14 2:31 
QuestionAn errors occured while building Pin
Member 1088091512-Jun-14 23:39
Member 1088091512-Jun-14 23:39 
AnswerRe: An errors occured while building Pin
Member 1088091513-Jun-14 1:27
Member 1088091513-Jun-14 1:27 
QuestionPlease post LAT and LONG example for specific location.... Pin
zeeshan00917-Apr-14 9:38
zeeshan00917-Apr-14 9:38 
AnswerRe: Please post LAT and LONG example for specific location.... Pin
Member 1088091513-Jun-14 2:41
Member 1088091513-Jun-14 2:41 
QuestionEARTHLib Pin
Member 105766996-Feb-14 4:30
Member 105766996-Feb-14 4:30 
AnswerRe: EARTHLib PinPopular
namth2994-Apr-14 22:34
namth2994-Apr-14 22:34 
QuestionForm not loading Google Earth Pin
Member 842394629-Apr-13 10:09
Member 842394629-Apr-13 10:09 
QuestionAdd GPS Pin
A-DeveloperZ23-Apr-13 1:37
A-DeveloperZ23-Apr-13 1:37 
QuestionDear Sir, Pin
Ethiopaninomaltt23-Feb-13 2:51
Ethiopaninomaltt23-Feb-13 2:51 
QuestionHow to get Coordiantes from cursor Pin
M.S.S.E21-Jan-13 23:57
M.S.S.E21-Jan-13 23:57 
QuestionWPF Compatibilty Pin
VK_00117-Nov-12 8:23
VK_00117-Nov-12 8:23 
QuestionThis demo just open once , GE dont run in second Pin
shindo2165-Sep-12 17:48
shindo2165-Sep-12 17:48 
AnswerRe: This demo just open once , GE dont run in second Pin
shindo2165-Sep-12 18:21
shindo2165-Sep-12 18:21 
GeneralRe: This demo just open once , GE dont run in second Pin
raddog14-Jan-13 12:54
raddog14-Jan-13 12:54 
QuestionMouse wheel zoom in/out doesn't work? Pin
sherifffruitfly23-Aug-12 18:40
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Questionplace mark icon Pin
mojimoj18-Mar-12 8:52
mojimoj18-Mar-12 8:52 
QuestionHi Pin
myazar16-Nov-11 9:31
myazar16-Nov-11 9:31 

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