Multiuser editing and versioning of terrain datasets
Terrain datasets inside an ArcSDE database support versioned editing. The benefits are similar to versioned editing of features. Complex workflow scenarios are supported that enable a terrain to be modified over time, by multiple groups, with rollback capability. What-if scenarios can be performed.
Rules for setting up a versioned terrain
- A terrain needs to be fully defined and built before being versioned. Use the Terrain Wizard or geoprocessing tools to build your terrain.
- Feature classes that are already versioned cannot be added to a terrain.
- Feature classes can participate in both a topology and a terrain.
- Feature classes can participate in multiple terrains.
- Schema changes are not permitted on versioned terrains. This means that after you version a terrain, you won't be able to add or remove feature classes.
- You version a terrain by registering the feature dataset it resides in as versioned.
Reconciling a database containing a terrain
Terrains can be composed of two different types of feature data: those in regular feature classes and those in embedded feature classes. Reconciliation of features in regular feature classes works normally, as if they didn't participate in a terrain. You do nothing different. The terrain simply keeps a record of where it needs to be rebuilt, locally, to keep in sync with changes that have taken place due to the reconciliation process. Embedded feature classes are different, though. They exhibit behavior unique to terrains.
The supported types of edit operations on embedded multipoint feature classes include add, delete, and replace. They work on areas of points, because there are typically so many of them. Any of these edit operations is a potential source of conflict if performed in the same area in parent and child versions. This is because conflicts of embedded features are based on the terrain's tile system rather than at the individual feature level. An edit within a tile is treated as if the entire tile has been modified. During reconciliation, a comparison is made between tiles. If the same tile has been modified between versions, there's a conflict. To resolve a conflict, one version's set of points for a tile will be selected. The conflicts are resolved automatically by applying the preference set in favor of either the target or edit version when starting the reconciliation process.
Whether you modify data in regular or embedded feature classes, you might need to rebuild the terrain after reconciling. Look at the Terrain Properties dialog box in ArcCatalog or the Terrain Layer Properties dialog box in ArcMap to determine if a rebuild is necessary. The build can be performed using the geoprocessing Build Terrain tool or from the Update tab on the Terrain Properties dialog box in ArcCatalog.