Until ArcGIS Pro 3.6 and ArcGIS Enterprise 12.0, any layout configured to run during diagram generation systematically applies to all the diagram features. Introduced with ArcGIS Pro 3.6, the Add Diagram Feature Selection To Layout tool can be used to select the diagram features to which the next active layout configured on the diagram template will apply.
The Diagram Feature Selection To Layout task looks like a diagram rule since it allows filtering out particular diagram features to be processed in a particular way during diagram creation, in the same way the Set Root Junction, Set Starting Point, or Add Diagram Feature Capability rules do. However, there are a few differences in the way diagram rules behave, so it can't be called a rule:
- Diagram rules are configured on a diagram template during the diagram rules phase. The Diagram Feature Selection To Layout task is configured during the diagram automatic layouts phase.
- Diagram rules only apply to the diagram features existing in the diagram graph that is currently in-build. The Diagram Feature Selection To Layout task always applies on the complete diagram graph.
- Diagram rules can be configured on a diagram template to filter out or flag particular diagram features to be processed by other rules. The Diagram Feature Selection To Layout task is configured to select diagram features to be processed by only the first active layout in the template layout sequence.
- Diagram features filtered out or flagged by diagram rules are kept along the diagram building phase and even beyond; for example, a root junction set during diagram building stays as a root junction in the generated diagram that opens. The diagram feature selection set built by the Diagram Feature Selection To Layout tasks is systematically clear once the first active layout is complete.
- Diagram rules always reapply at diagram update. The Diagram Feature Selection To Layout tasks only reapply when updating the diagram with the Re-apply automatic layouts on the updated diagrams option checked.
All these considerations show that the Diagram Feature Selection To Layout task is neither a diagram rule nor a diagram layout. It is a kind of rule specific to layouts.
Diagram Feature Selection To Layout task process
During the diagram automatic layouts phase, you can configure Diagram Feature Selection To Layout tasks to query the diagram features you want to be automatically laid out during diagram generation. When you chain multiple Diagram Feature Selection To Layout tasks, each resulting diagram feature selection set is merged with the previous one. Then, the first layout configured as an active layout after these tasks considers the currently selected diagram features and applies to these only selected diagram features. Once this first active layout completes, the diagram feature selection set is systematically cleared. Therefore, to apply a sequence of multiple layouts to the same diagram feature selection during diagram generations, you must configure the same Diagram Feature Selection To Layout tasks that allow you to build the diagram feature selection you expect before each active layout you configure on a diagram template.
Diagram Feature Selection To Layout task configuration
You can configure a Diagram Feature Selection To Layout task on a template with the Add Diagram Feature Selection To Layout tool.