Before beginning the cache generation process, you must consider your requirements and make the appropriate design decisions to ensure that your content can provide the best value and information to your users. Consider the following when generating caches.
Scales
When you cache a map, you draw it at more than one scale so users can zoom in and out of the map. When choosing properties for your cache, you must determine what scales you want to use for caching. ArcGIS Pro can also automatically generate scales.
You must also determine the maximum level of detail the content will be used at, such as at the global, state, county, city, or neighborhood level.
Interoperability
To allow users to combine the content you have shared with other publicly available layers, you must ensure that the coordinate system used while authoring the map is the same as the publicly available layers. If the coordinate systems do not match, the content will be re-projected and there will be a reduction in performance. Once authored, the tiling scheme used by the layers must match the scales selected.
Note:
Vector and scene layers require that the consecutive scale values in level of details be a ratio of 2.
Purpose
When publishing cached services, you must consider whether the content will be used as a basemap or as an overlay on other basemaps.
- If the content will be used as a basemap, see Design a map to overlay on maps in ArcGIS Online, Google Maps, or Bing Maps.
- To prepare a cached operational map layer, see Author a multiscaled map. Raster tile layers in PNG and mixed format and vector tile layers allow visibility to underlying content.
Note:
When caching operational map layers that need to be overlayed on basemaps, you must determine whether the overlay should allow underlying content to be visible.
Operations and capabilities
When choosing the type of cache layer you will use, you must identify the operations users will run on the web layer. For instance, users may need support for query, identify, pop-up, or legend operations on their web layers.
Cached map image layers support the legend, query, and identify operations, while web tile layers do not. If you need to support pop-ups with web tile layers, see Configure pop-ups (Map Viewer Classic) and Use web tile layers for ArcGIS Pro.
Update frequency
A cache represents a snapshot of your map at a certain point in time and works best with maps that are not live. If the data on your map needs to be live and display updates without a time delay, caching is not an appropriate solution.
Cached content should not become outdated and must be updated regularly to remain relevant. Examples of data like this include street maps, imagery, and terrain maps.
If your map contains only vector data, it is recommended that you use a vector tile layer for sharing the content. See Manage tile layers for more information on updating and rebuilding vector tile layers.
The frequency at which you update your cache will depend on the time it takes to acquire new source content and generate the cache and the server resources you have available to you.
If your data changes frequently, it is recommended that you use a staging server to build your cache to allow your production server to be used for other operations. If you cannot generate caches on a staging server, you should consider scheduling cache updates during down times on your production server.
You can also generate caches using the ArcGIS Pro Manage Tile Cache toolset.
Client consumption
When generating a cache, consider the clients that will be rendering the cache content, such as desktop, mobile , or web apps. You can modify the cache dpi to support the resolution of the different devices.
Performance
Consider the following to provide the best end user experience:
- How responsive does the content need to be?
- What should the rendering time of your cached map services be?
- How many users are expected to use the content?
Generating a test cache on your server setup can help you determine whether you have enough resources to sustain these requirements.
Design a map to overlay on maps in ArcGIS Online, Google Maps, or Bing Maps
When building a map cache, you can choose to match the cache's tile dimensions and scales to those used by ArcGIS Online, Google Maps, and Bing Maps. Doing so will produce better performing overlays in client applications. See Author a custom basemap for more information.
This requires using the WGS 1984 Web Mercator (auxiliary sphere) coordinate system and designing your map to be legible at the different scales used by ArcGIS Online, Google Maps, and Bing Maps. Set the scale ranges on your map layers so that they display an appropriate amount of data while still presenting legible labels and symbols.