Cache management in ArcGIS Explorer

There are two types of caching used by ArcGIS Explorer: memory caching and disk caching.

Memory caching

Memory caching refers to assigning an amount of physical memory (RAM) for use by ArcGIS Explorer. For optimum performance you can set the amount of memory assigned for each type of data used. For example, if your 3D view contains many elevation data sources and very few 3D features, you can allocate more RAM for the elevation layers. Often an ArcGIS Explorer document that is performing poorly can become very interactive through well defined memory cache settings.

Configuring the memory cache by data type

1. Click the Tools menu and click Options.
2. Click Cache at the left of the dialog box.
3. Click Memory Cache.
4. Enter the memory allocation values, in megabytes, for each memory type.
5. The current memory usage for each type, and the percentage of its allocated size, is detailed on the text box and horizontal graph next to each item.
6. Click OK on the Options dialog box.

Tips

• The total memory cache size is automatically calculated as the sum of the individual settings.
• Your total memory cache size should not exceed your physical memory (RAM).
• These values will apply to all future ArcGIS Explorer sessions, so you should consider all the ArcGIS Explorer maps you will be working with when defining the memory cache settings.
• ArcGIS Explorer will not automatically balance the allocation of memory used for each data type. If you allocate a small amount of memory to a particular data type and subsequently create a document that uses that data type, it will start paging the data well before physical memory is exhausted.

Disk caching

Disk caching creates a temporary file, or cache, for each layer in ArcGIS Explorer that helps you display and navigate your data efficiently. A disk cache stores the data and information that allows ArcGIS Explorer to better manage your environment by controlling levels of detail. The status of a cache can be on demand, partial (containing some details of the layer), or full (containing all the details the layer has to offer). As you navigate your layers in ArcGIS Explorer, the parts of the data you zoom to are cached on demand to disk. Revisiting these areas subsequent times will be faster because they are already cached. The name of layer's disk cache is a concatenation of its display name and global unique identifer (GUID). Saving the ArcGIS Explorer document or creating a layer (.nmf) file will ensure that the disk cache is not inadvertently deleted, as well as retain a link to the cache for future use. When the display for a layer changes, its disk cache is automatically deleted and recalculated. You can manually clear the entire disk cache for a layer by clicking Manage Layers on the Tools menu; then select the layer and click the Clear Layer Cache button.

When you add content to the map that is not a globe service you'll be able to control the kind of caching to perform on the layer. The Caching Feature Layers dialog box of the Add Data wizard allows you to choose what caching scheme you want for the layer you are adding. You can choose one of three options: creating a cache for the layer, creating a session cache for the layer, or never caching the data to disk. The last two options can be augmented by refreshing the cache during the session at a specified interval.