All domain elements in WaterCAD 2024 have an editable GIS-IDs property which can be used for maintaining associations between records in your source file and elements in your model. These associations can be one-to-one, one-to-many, or many-to-one.

ModelBuilder can take advantage of this GIS-IDs property, and has advanced logic for keeping your model and GIS source file synchronized across the various model to GIS associations.

The GIS-IDs is a unique field in the source file which the user selects when ModelBuilder is being set up. In contrast to using Label (which is adequate if model building is a one time operation) as the key field between the model and the source file, a GIS-IDs has some special properties which are very helpful in maintaining long term updating of the model as the data source evolves over time.

In addition, WaterCAD 2024 will intelligently maintain GIS-IDs as you use the various tools to manipulate elements (Delete, Morph, Split, Merge Nodes in Close Proximity).

• When an element with one or more GIS-IDs is deleted, ModelBuilder will not recreate it the next time a synchronization from your GIS occurs if the "Recreate elements associated with a GIS-IDs that was previously deleted from the model" option is left unchecked.
• When an element with one or more GIS-IDs is morphed, the new element will preserve those GIS-IDs. The original element will be considered as "deleted with GIS-IDs", which means that it will not be recreated by default (see above).
• When a link is split, the two links will preserve the same GIS-IDs the original pipe had. On subsequent ModelBuilder synchronizations, any data-change occurring for the associated record in the GIS can be cascaded into all the split link segments (see "Step 4--Additional Options" ).
• When nodes in close proximity are merged, the resulting node will preserve the GIS-IDs of all the nodes that were removed. On subsequent ModelBuilder synchronizations into the model, if there are data-update conflicts between the records in the GIS associated with the merged node in the model, updates from the first GIS-IDs listed for the merged node will be preserved in the model. Note that in this case, the geometry of the merged node can't be updated in the model. For synchronizations going from the model to the GIS, data-updates affecting merged-nodes can be cascaded into all the associated records in the GIS (see "Step 4--Additional Options" ).

To support these relationship (specifically one to many), GIS-IDs are managed as a collection property (capable of holding any number of GIS identifiers).

A variety of model element(s) to GIS record(s) associations can be specified:

• If the GIS-IDs collection is empty, there is no association between the GIS and this element.
• If there is a single entry, this element is associated with one record in the GIS.
• If there are multiple entries, this element is associated with multiple records in the GIS.
• More than one element in the model can have the same GIS-IDs, meaning multiple records on the model are associated with a single record in the GIS.