Globe services

A globe service provides a 3D view of a globe originating from an ArcGlobe document (.3dd). To create a globe service, you need to first create the globe document, then publish it as a service. Once you create the service, supported clients such as ArcGlobe, ArcGIS Explorer, and ArcReader will be able to access the globe service remotely.

The steps to create a globe service are as follows:

1. Prepare an ArcGlobe Document, ensuring that the document, data, and layer caches are accessible from all server object container (SOC) machines.
2. Using ArcCatalog or ArcGIS Server Manager, create and start the globe service.
3. Generate a data cache for optimal performance, if not already present.

The following sections explain the process of preparing, creating, and using a globe service, as well as how to improve the rendering speed of the service by creating a globe cache.

Creating the globe document

The first step to deploying a globe service is creating the ArcGlobe document. You'll need to have ArcGIS Desktop with the 3D Analyst extension to do that. For some helpful introductory information about working with ArcGlobe, see the topic ArcGlobe 3D display environment in the ArcGIS Desktop Help.

A globe service consists of a collection of layers that can be added individually to an application as data. This differs from a map service, which references the entire map document when added to an application as data. Because the ingredients of a globe service are these individual layers, globe document properties such as ambient lights, sun position, background color, and exaggeration are not reflected in a globe service.

Removing ArcGIS Online layers

The default globe in ArcGlobe 9.3 consists of layers from ArcGIS Online services. You should remove these default layers before publishing the globe service. This is because globe services (such as the ones on ArcGIS Online) cannot be published within other globe services.

If you still want viewers to see the ArcGIS Online content along with some of your own layers, you should publish your service without the ArcGIS Online layers. Then, create either an ArcGlobe document, a 3D ArcReader document, or an ArcGIS Explorer map and add the following layers:

• The globe service you just published
• The ArcGIS Online layers (See the ArcGIS Online home page for information on how to connect to ArcGIS Online services and add the layers to your map.)
• Any other services you want to include

You can post this document on a Web page or in a shared location. This workflow ensures that clients retrieve each globe service in the most efficient way.

Note: If you'll be publishing many globe services, you might want to change your ArcGlobe preferences so that the default globe does not start with ArcGIS Online layers.

Tips for preparing documents for globe service publishing

When designing a globe document to be published as a globe service, consider the following tips for optimum performance:

• Set scale-dependent rendering for layers: Use scale-dependent rendering to ensure that unneeded layers do not draw when the globe is zoomed out/in. Data-intensive or highly detailed layers may be more appropriate only when the globe is zoomed in to a larger scale.
• Simplify layer symbology: Complex symbols take longer to draw. Use simple line and fill symbols where possible, avoiding symbology that contains multiple layers, complicated dash patterns, or outlines.

• Use raster compression: The Cache tab of the Layer Properties dialog box contains options for raster compression. ArcGlobe offers two types of lossy spatial compressions, JPEG and DXT. Using compression on image data reduces cache storage space by spatially averaging the distribution of colors in an image.

  The JPEG compression format reduces the size of the cache generated by compressing the data tiles in JPEG format. ArcGlobe gives you control over what degree of compression to use. This is exposed as a relative quality of the image data. The default, a quality of 75 percent, usually gives acceptable results and is recommended.

  DXT compression is another lossy image compression format that is directly supported by the driver of your graphics card hardware. DXT-compressed tiles are optimal for high-resolution imagery data. DXT-compressed data tiles improve visualization performance, as their size does not grow when loaded into memory, allowing the client to have a smaller memory footprint. However, the tile size of DXT-compressed data on disk can be significantly larger than JPEG-compressed tiles, depending on the JPEG quality selected (usually the DXT-compressed data is 8-12 times larger than the corresponding-JPEG compressed tiles).

  Note that some server class machines (especially older ones) might not have a graphics card that supports hardware-based compression of DXT tiles. In this case, ArcGlobe and ArcGIS Server are equipped with a software-based emulation that will allow you to compress data caches into DXT-compressed tiles.

• Compress the pixel value range to 16 bits: Compressing the pixel value range to 16 bits is a default setting that limits raster displays to 65,536 colors. Usage of this option is recommended. Only use 24 bits of color resolution if high-fidelity imagery is required.

  Use this same option to compress the elevation range of a raster surface to 16 bits. Uncheck this option to use 32 bits of range, which is useful only if your elevation source has submeter vertical accuracy.

• Increase the minimum cell size of raster layers: If your raster data resolution is very high, you can progressively increase the minimum cell size, thereby decreasing the size of the data cache. Set the minimum cell size at the highest value that is appropriate for your data and the needs of your audience.
• Remove unused layers: Verify that your globe document is free of layers that are not intended to be part of the globe service.
• Remove any globe service layers from your globe document. Globe services cannot be published within other globe services. If you publish a document that includes globe service layers, those layers will be removed from the resulting globe service. The server log files will include a message about the removed layers.
• If your globe service contains a layer from a 2D ArcGIS Server map service accessed through a local, or LAN, connection, your SOC account must be a member of the agsusers group on the machine hosting the map service.

Creating the globe service

To create a globe service, follow the steps in Publishing a GIS resource to the server. Choose to publish a globe service and browse to the globe document that you want to publish.

Note that when you publish a globe service using these steps, the wizard will pick the first cache directory registered from among the ArcGIS Server cache directories. If you want to use a different cache directory, use the Add New Service wizard instead. The topic Adding a new service contains instructions for the Add New Service wizard.

Creating a globe cache

For faster display of your globe services, you can create a cache that stores prerendered image tiles on disk. When someone uses a globe service client, such as ArcGIS Explorer or ArcGlobe, to view an area of your service, your server can simply retrieve the tile from the cache instead of taking the time to render the view. It's up to you to determine the size of your initial cache, but you should consider creating at least a partial cache to optimize the performance of your services. The scope of the cache you choose to build may depend on the resources that you have available for creating and storing the cache. Information on globe caching techniques is located elsewhere in this documentation.

Learn more about globe caches.

Configuring Web access for the service

By default, globe services are enabled for Web access. To disable or limit Web access to the service, see Securing Web services.

When a globe service has Web access enabled, users of client applications can access the service through HTTP. Supported clients of these Web services are the same as the clients that can view a globe service through local connections, namely ArcGlobe, ArcCatalog, ArcGIS Explorer, ArcReader, and ArcGIS Engine applications.

Allowed operations for globe Web services are Globe, Animation, and Query. All three are enabled by default.

• Globe is always enabled and cannot be disabled, as it allows you access to the globe data.
• Animation allows clients to access any animation contained in the globe document.
• Query allows you to perform find and identify functionalities on feature data.

For a list of the methods associated with each operation, see Limiting what users can do with a service in the topic Tuning and configuring services.

When using a globe Web service, ArcGIS Server employs two methods for serving the data tiles. The first (default) is via a query string approach where the client has a knowledge to request data tiles by specifying rows and columns. Simply enabling the Web service will activate this mode; there is nothing you'll need to do additionally as the Web service administrator.

If you associate the cache directory with a virtual directory on your Web server, ArcGIS Server can instead use a static HTTP GET to fetch the data tiles. Exposing the cache through a virtual directory has the added benefit of leveraging the IIS Web server's caching, which will help in performance. Be sure to allow Read permissions to the virtual directory.



Here's how to associate your globe cache directory with a virtual directory:

1. Create the virtual directory using your Web server administration software (such as IIS Manager). The virtual directory should reference your globe service's cache directory.
2. Create an administrative connection to the server that contains the globe service.
3. Right-click the administrative connection you created to open the Server Properties dialog box.
4. Click the Directories tab. Choose Cache Directory rom the Directory Type drop-down list.
5. Choose the Cache Directory you want to expose through a virtual directory and click the Edit command. You can now specify the virtual directory name for your cache directory.

Note: You need to make sure that the MIME Map types for your virtual directory use a wildcard mapping (.* ) for allowed file types, since the tiles of a globe cache do not have a file type association.

Using the globe service

Once you've created the service and started it, users of client applications, such as ArcGlobe and ArcGIS Explorer will be able to consume your globe service by connecting to your GIS server and adding the service as data in their documents. Clients can view globe services through either local (LAN or WAN) or Internet connections.

Does the Web ADF contain controls for consuming globe services?

The Web and mobile Application Developer Frameworks (ADFs) for ArcGIS Server do not have controls for consuming globe services. ArcGIS Explorer is the recommended application for viewing globe services in a lightweight client.

The only way to view ArcGIS Server services in 3D in a Web application is to use the ArcGIS JavaScript Extension for Virtual Earth to view a cached map service draped over the Virtual Earth globe.

Web access

By default, globe services are enabled for Web access. Web service developers can work with these through the globe service's Web Service Description Language (WSDL). The URL of a Web-enabled globe service follows this pattern:

http://<server name>/<instance name>/services/<folder name (if the service resides in a folder)>/<service name>/GlobeServer

For example, if you had a service Toronto in a folder Canada running on a server myServer with the default instance name of ArcGIS, the URL would be as follows:

http://myServer/arcgis/services/Canada/Toronto/GlobeServer