You can use scale visibility filters to control the display of tiles in a manager layer. For details on visibility filters, see the section The Scale Filters on page 71.

When a scale visibility filter has been set for a tiled layer, this layer will be displayed if the scale factor set for its manager view is within specified scale limits. Otherwise, it will be hidden. When a tiled layer is visible because the zoom factor of the manager view allows it, visible tiles are automatically locked and thus loaded into memory. In the same way, when a tiled layer is hidden because the zoom level of its view exceeds a certain value, all the locks set on visible tiles are released and the tiles are removed.

Scale visibility filters are generally used to activate load-on-demand for zoom factors between a minimum and a maximum scale value. If you consider a map scanned with a scale of 1/1,000,000, you can set visibility filters so that its layer is visible for scale factors ranging from 1/2,500,000 to 1/500,00.