Globe services

A globe service provides access to a 3-D 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 follow in creating a globe service are:

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 the ArcGIS Server Manager, create and Start the globe service, optionally enabling web access.
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 3D Analyst Extension to do that. For some good 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, exaggeration, and so forth are not reflected in a globe service.

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 property sheet 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%, 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 desktop application 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 sub-meter 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.

Creating the globe service

To create a globe service, follow the steps in  Publishing a GIS resource to the server .

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 wish 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 pre-rendered 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 how big of an initial cache you would like to create, 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. A good place to start is How globe caches work. See also Building globe caches and Tips and best practices for 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 a service.

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 server object through local connections, namely ArcGlobe, ArcCatalog, ArcGIS Explorer, ArcReader, and ArcGIS Engine applications.

Allowed operations for globe Web service are Globe, Animation, and Query. All three are enabled by default. Globe is always enabled and can not be disabled as it allows you access to the globe data. Animation allows you to publish along with the Globe 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 Securing a service.

When using a globe Web service, ArcGIS Server employs two methods for serving the data tiles. The first and default is via a query string approach, where the client has a knowledge to request for 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 webservice administrator.

If the cache directory is exposed as a virtual folder, ArcGIS Server can instead use a Static HTTP GET to fetch the data tiles. To do this, you will need to expose your cache directory as a virtual folder with a read permission. Additionally you'll need to register the virtual folder name as part of the Cache directory in the ArcGIS Server Properties dialog.

Exposing the cache folder as a virtual folder has the added benefit of leveraging the IIS Web server's caching, which will help in performance. Follow the following steps to do so:

1. Create an administrative connection to the server that contains the globe service.
2. Right-click on the administrative connection you created to invoke the ArcGIS Server Properties dialog.
3. Select the Directories tab. From the Directory Type drop down select Cache Directory.
4. Select the Cache Directory you want to expose as a virtual folder and click the Edit command. You can now specify the virtual folder name for your cache directory.

Note that when exposing your cache directory as a virtual folder for a globe Web service access, you'll need to make sure that the MIME Map types for your cache directory that's exposed as a virtual folder uses a wildcard mapping (.* ) for allowed file types, since the tiles of a globe caches 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.

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 named Toronto in a folder named Canada running on a server named myServer with the default instance name of ArcGIS, the URL would be:

http://myServer/arcgis/services/Canada/Toronto/globeserver.