Tips for authoring globe services
To make a globe available on ArcGIS Server, you need to author the globe in ArcGlobe, publish it to the server, then use the resulting globe service in a client application. Many of the things you can do with globe services require some preparation in the initial authoring phase. These considerations are listed below to help you when making a globe intended to be published as a service.
Upon publishing your globe document, you'll get a chance to examine the globe for any potential authoring or performance issues you may have overlooked. Analyzer messages are used to quickly identify performance improvements before you publish.
Remove globe service layers, including the default ArcGIS Online layers
Embedding a globe service within another globe service is generally detrimental to performance and can also cause problems with out-of-date caches. If you want another globe service to participate in your end-client application, you should connect to that service directly in the application.
Be especially aware that the default globe in ArcGlobe contains globe service layers from ArcGIS Online services. Built-in analyzers require you to remove these layers before publishing the globe service.
If you still want viewers to see the ArcGIS Online content along with some of your own layers, you should create 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 (Get information on how to connect to ArcGIS Online services and add the layers to your globe.)
- Any other services you want to include
You can post this document on a web page or share through ArcGIS Online. This workflow ensures that clients retrieve each globe service in the most efficient way.
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. You can do this by clicking Customize > ArcGlobe Options > Default Layers.
Set scale-dependent rendering for layers
Set distance ranges on your layers to ensure that unneeded layers are not drawn 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. Use the Globe General tab of the Layer Properties dialog box to set distance ranges.
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 allows 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. Open the layer properties for your image and click the Cache tab to access the raster data settings. 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.
The Compression tab on the ArcGlobe Options dialog box ensures that all new image and elevation layers are added by default with 16-bit compression. Changing this setting applies to all future ArcGlobe documents, as it is an application setting, not a layer-based setting.
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. Open the layer properties for your image and click the Cache tab to access the raster resolution settings. Set the minimum cell size at the highest value that is appropriate for your data and the needs of your audience.
Remove unused layers
Check that your globe document is free of layers that are not intended to be part of the globe service. Ensuring your globe is clear of data unrelated to the purpose of the document helps improve usability by other parties and overall performance.
Verify ArcGIS Server permissions
Before you publish a globe service to ArcGIS Server, you'll need to explicitly:
- Grant the ArcGIS Server account permissions to any data referenced by the layers in your globe document. This process is described in detail in: Making your data accessible to ArcGIS Server.
- Register your data with ArcGIS Server in ArcGlobe. Data registrtion helps you verify that ArcGIS Server can access the data referenced by your globe document. If you attempt to publish a globe service that references data from an unregistered location, the data will be copied to the server during the publishing operation. Each of these scenarios is further explained in About registering your data with ArcGIS Server.
Generate a globe cache
You should generate the fullest data cache that is practical and applicable. When a tile is already in the data cache, ArcGIS Server does not have to generate it at serving time but rather serves the tile as requested by clients. The actual caching happens after you've published your map as a service. This is the optimum mode of serving.
After publishing your ArcGlobe document as a service, use the following caching recommendations:
- Raster layers as elevation must be fully cached before being consumed as a globe service. Elevation layers do not support on-demand tile generation.
- It is highly recommended that you build a full data cache for feature layers as vectors (such as extruded polygons, multipatches, and 2D line and point features drawn as vectors) before they are consumed as a globe service. Generating a full data cache for features as vectors is a fast process and is recommended for optimal results. Note, however, that on-demand data caching is still available for such layers.
- For rasters as images and rasterized features, generate caches for optimal performance as desired. Rasterized features allow partial cache generation and should include the levels of detail that you expect your users to interact with most.
For other general considerations that apply to authoring both map and globe services, see Map authoring considerations for ArcGIS Server.