How to... > Extend discrete Scales of an external Service

In some cases it is useful to extend discrete scales of an external service when combining it with an service in a WebOffice 10 R3 project. E.g. an OpenStreetMap service serves as background for editable layers. Because the largest scale of the cached external OSM service (1:2,257) would not be suitable for detailed editing operations, additional discrete scales can be defined in the map collection.

Providing an additional scale (...|50) for editing operations

Note: Detailed information about the configuration of the map collection can be found in chapter Map Collection.

Therefore, define all the used scales of the cached service and the desired additional scales in the parameter "Discrete scale levels". Depending on the configured scales, the display of cached services can be different.

Note: Explicitly provided discrete scale levels will be displayed in any case. In combination with cached map services there can arise the following cases:

- a) A discrete scale level is defined that is not supported by the cached map service and lies beyond available LOD (Level Of Detail) levels of this cached map service (e.g. very large scales). When selecting this scale, the concerned cached map service will not be displayed.

Example: The scale 1:50 is beyond the LOD of an OpenStreetMap services. Therefore, in this scale no OSM service will be displayed.

- b) A discrete scale level is defined that is not supported by the cached map service and lies within the available LOD levels of the cached map service . When selecting this scale, the concerned map service will be integrated dynamically.

Example: The scale 1:3000 is within the LOD of an OpenStreetMap service. Therefore, a dynamic OSM service will be displayed.

- c) The cached map service is displayed dynamically in all LOD levels due to a different projection, then the service will be displayed in all provided discrete scale levels.

Example: The main map service does not used Web Mercator Auxiliary. The OSM service will be reprojected and displayed at any scale.

With this option it is possible to provide very large scales for e.g. editing operation on a dynamic map service while combining it with background cached map service in common scale levels.

Three editing layers combined with an OSM map service. The cached OSM service is displayed in all scales that are conform with its LOD

Three editing layers with an OSM map service. Due to the scale 1:50 the cached OSM service is not displayed.

For a better performing configuration it is recommended to set a scale range within the map views for the cached map service. Define the scale range depending on the available LOD levels of the cached service. When selecting a scale beyond this scale range the system does not have to check again if the selected scale is within or beyond the LOD level of the cached service and therefore if it is necessary to display the service or not.

Define a scale range for the cached map service

Note: Detailed information about the configuration of map views can be found in chapter Map View.