Function Description
The snapshot layer is a special layer group. The layers in the snapshot Layer Group are all snapshot layers of the map. The snapshot layer is drawn in a special way. It is drawn only when it is displayed for the first time. After that, when browsing the map, if the map Visible Bounds: does not change, the snapshot layer will not be redrawn, that is, the snapshot layer will not be redrawn with the Refresh Map; If the map Visible Bounds: changes, a refresh draw of the snapshot layer is automatically triggered. Snapshot layers are one way to improve map display performance.
Because the snapshot layer is a special Layer Group, the Groupe layer object (LayerGroup) can be added to the snapshot layer, but the snapshot layer cannot be added to the snapshot layer, and the snapshot layer cannot be added to the Group Layer object (LayerGroup object).
Application Scenario: In the process of mapping, some layers have a large amount of data, which will affect the refresh efficiency of the map. In this case, the layers that must be displayed with low refresh frequency and large amount of data can be added to the snapshot layer. Without changing the MapVisible Bounds:, the layers in the snapshot Layer Group will not be refreshed. The display performance of the map is improved.
Operating instructions
- In an empty area of Layer Manager, right-click and select the New Snapshot Group option to create a snapshot Layer Group.
- Select one or more layers and move them to the snapshot Layer Group. These layers can be used as snapshot layers. If the Map range remains unchanged, the layers under the snapshot Layer Group will not be refreshed.