Tips and best practices for map caches

The tips below can help you achieve the best appearance and performance for your map caches. The tips are arranged in the following categories:

Preparing the map document

Creating the cache

Image format

Although you should try to match tiling schemes when building your caches, you do not need to match the image format. After importing a tiling scheme file, you can change the image format before you create the cache. Use these guidelines to choose the appropriate image type for each individual cache:

  • Use JPEG format for raster-based basemaps with a lot of color variation, such as imagery.
  • Use JPEG or PNG formats for vector-based basemaps such as street maps. Maps with just a few simple colors should use PNG.
  • Use PNG for overlay services, such as boundaries, road networks, or any features that require background transparency.
  • Avoid using PNG 8 if your map has more than 256 colors.
  • Avoid using PNG 24 if your tiles will be viewed in Internet Explorer 6.

Maintaining the cache