Layer description tags are applied at both the Configuration MXD and Map Service MXD level. These tags carry behaviour through to the Dekho Map Client and can be used to improve performance for the Dekho Users. A good approach is to follow the below steps:
§ To avoid performance issues with the selection and identify tools make use of the IDENTIFY=FALSE and MAP_SELECTABLE=FALSE tags. Use of these tags avoids layers (particularly basemap layers) from being unnecessarily queried by default. Most users do not typically think to turn the selectability of layers off before making a selection.
§ Ensure you apply TILED=TRUE to all Cached Map Services within the Configuration MXD.
§ If you have multiple basemaps (e.g. different imagery acquisition dates), make use of the EXCLUSIVE=TRUE tag (see figure 6). This avoids the Dekho Map client unnecessarily calling multiple basemap services when it should only be calling one.
Figure 6 - Allow Dekho users to toggle between basemaps.