- GPoint: This is the class representation of a geographical point and exposes latitude and longitude as its two properties.
- GPoints: This class represents a collection of GPoint objects.
- GIcon: Represents a custom icon that is used as an overlay on the map. The GIcon class exposes the following properties: the Image URL, which as the name suggests, is the URL of the image used to represent the icon; ShadowImageURL is the URL of the shadow associated with the icon; IconSize and ShadowSize represent the size of the icon and the shadow, and the last two properties are IconAnchor and InfoWindowAnchor, which specify the point where the icon should be anchored to the map relative to its top-left corner and the point where the Info window should be anchored to the map.
- GLine: This is a line that the user wishes to overlay on the map. By default it takes a collection of points (GPoints) as an argument in its constructor. It is also possible to set the color of the line as well as its weight and opacity through an overloaded constructor.
- GMarker: This is the .NET representation of the Google Maps class GMarker. The default constructor accepts an instance of a GPoint class. It also has an overloaded constructor that takes a GIcon along with the GPoint in case the developer wishes to use a custom icon to represent the marker.
- GSize: Represents a two-dimensional size measurement.
- JScriptGenerator: This is an internal class and has more of a helper function. It generates most of the JavaScript functions that are needed by the control.
- HelperColorConvertor: This class is used to convert a color into its equivalent Hex value. This class is marked as internal.
- HelperDataResolver: This is an internal class that helps in data binding and has just one method. The method casts a datasource object into an object that implements the IEnumerable interface. The help file that describes in detail the different methods and properties of the classes involved is available as a download.
Getting Started in ASP.NET
Before we use the ASP.NET control in our application, there are a few things that need to be taken care of to ensure that it works as desired.
Before we use the ASP.NET control in our application, there are a few things that need to be taken care of to ensure that it works as desired.
Web.config File
The GMAP control renders itself as a DIV tag, however for non-Internet Explorer Browsers, ASP.NET renders the div tag as tables. If you want the page to render the GMAP control properly in other browsers such as Netscape and Firefox, include the browser cap section shown in Listing 1 into the Web.config file of your application.
The GMAP control renders itself as a DIV tag, however for non-Internet Explorer Browsers, ASP.NET renders the div tag as tables. If you want the page to render the GMAP control properly in other browsers such as Netscape and Firefox, include the browser cap section shown in Listing 1 into the Web.config file of your application.
Page Configuration
Google has certain recommendations for the HTML standards on pages that contain the map to make sure that the layout is predictable across different browsers. A detailed description of the same can be found in the Google maps documentation. It is imperative that you follow these standards, especially if you plan to overlay lines on your map. For lines to be rendered on the map, you need to include the VML namespace in the HTML page for Internet Explorer browsers. Make sure that you don't forget to do this, because otherwise the lines will not be displayed in Internet Explorer. The HTML tag of your page should at the minimum look like the snippet below:
Google has certain recommendations for the HTML standards on pages that contain the map to make sure that the layout is predictable across different browsers. A detailed description of the same can be found in the Google maps documentation. It is imperative that you follow these standards, especially if you plan to overlay lines on your map. For lines to be rendered on the map, you need to include the VML namespace in the HTML page for Internet Explorer browsers. Make sure that you don't forget to do this, because otherwise the lines will not be displayed in Internet Explorer. The HTML tag of your page should at the minimum look like the snippet below:
<HTML xmlns:v="urn:schemas-microsoft-com:vml">
Adding to the Toolbar
This step is optional; however if you are using Visual Studio .NET as your IDE, I would recommend that you go ahead and add the GMap control to your toolbox. The advantage of doing so is that you can easily drag and drop the GMap control onto an ASPX page like any other ASP.NET control, and Visual Studio will automatically register the control on your page. Figure 1 shows the GMap control on the toolbar.
This step is optional; however if you are using Visual Studio .NET as your IDE, I would recommend that you go ahead and add the GMap control to your toolbox. The advantage of doing so is that you can easily drag and drop the GMap control onto an ASPX page like any other ASP.NET control, and Visual Studio will automatically register the control on your page. Figure 1 shows the GMap control on the toolbar.
Creating a Basic Map Using the Control
Since we are done with the setup, let's go ahead and create a simple example using the control. We will add the GMap control to the page, set its dimensions, and make it center and zoom at a particular point. For the sample application used in this article, I have saved the map key in the Web.config file and will be setting the GoogleMapKey property of the control from the config file. I will be setting the map type of the control to be that that of "Map." In case no map type is specified, the control defaults to the preset "Map." The GMap Control also supports satellite and hybrid map types. Make sure that you center and zoom at a point, otherwise all that will show up will be a grey area. Listing 2 shows the code for this example and Figure 2 shows the output.
Since we are done with the setup, let's go ahead and create a simple example using the control. We will add the GMap control to the page, set its dimensions, and make it center and zoom at a particular point. For the sample application used in this article, I have saved the map key in the Web.config file and will be setting the GoogleMapKey property of the control from the config file. I will be setting the map type of the control to be that that of "Map." In case no map type is specified, the control defaults to the preset "Map." The GMap Control also supports satellite and hybrid map types. Make sure that you center and zoom at a point, otherwise all that will show up will be a grey area. Listing 2 shows the code for this example and Figure 2 shows the output.
Setting the GMap Control Properties
Let's go ahead and set some properties to the basic example we just created. The GMap control exposes a set of properties that allows the developer to customize the control to his or her needs. If we wish to give the user the flexibility to change the view, we set the ShowMapTypeControl property of the control to true. By default, the user is able to drag the map, however, if we do not wish the user to drag the map around, we can set the EnableDragging property to false. To allow the user to be able to scroll or zoom, set the ScrollControlType property of the control. There are three different options: "large," "small," and "zoom only," to correspond to the controls offered by Google. Listing 3 shows the source code and Figure 3 shows the output in the browser.
Let's go ahead and set some properties to the basic example we just created. The GMap control exposes a set of properties that allows the developer to customize the control to his or her needs. If we wish to give the user the flexibility to change the view, we set the ShowMapTypeControl property of the control to true. By default, the user is able to drag the map, however, if we do not wish the user to drag the map around, we can set the EnableDragging property to false. To allow the user to be able to scroll or zoom, set the ScrollControlType property of the control. There are three different options: "large," "small," and "zoom only," to correspond to the controls offered by Google. Listing 3 shows the source code and Figure 3 shows the output in the browser.
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