Building a geometric network from existing simple feature classes
This topic applies to ArcEditor and ArcInfo only.
Although geometric networks can be both created and edited in ArcInfo and ArcEditor, they are read-only in ArcView.
The Build Geometric Network wizard discovers the connectivity for a group of feature classes in a feature dataset and promotes them from simple feature types (lines and points) to network feature types (edges and junctions).
When you build a geometric network, the feature classes must already exist in the feature dataset. However, they can be empty. After the network has been built, you can add new network feature classes.
Geometric networks are built in ArcCatalog.
- Right-click the feature dataset that will contain the network.
- Point to New.
- Click Geometric Network.
- Read the information on the first panel and click Next. If you don't want this screen to appear every time you create a new geometric network, click the checkbox for Skip this screen in the future.
- Enter a name for the new geometric network or accept the default name.
- Specify whether snapping should occur during geometric network creation and set the snapping tolerance. The default value will be set to the x,y tolerance of the feature dataset.
- Click Next.
- Click the feature classes that you want to include in this geometric network.
- Click Next.
- If all of your feature classes contain coordinate z-values, you can choose to have the connectivity based on x, y, and z values and can choose to set the z snapping tolerance. The z-tolerance (0.001 meter in real-world units). Choose Next to use z-values for connectivity or choose No and click Next to not use z-values for connectivity.
- If any of the feature classes selected to participate in the network contain an enabled field, you can choose to keep the enabled values or reset them to true. Click No to enable all network features. Otherwise, Persist enabled values is selected by default.
- Click Next.
- Click the dropdown under Role and specify if any of your feature classes should be Complex Edges, otherwise, accept the default of Simple Edge.
- Click the dropdown under Sources/Sinks for any junction feature class to act as sources or sinks for modeling flow direction. Otherwise, accept the default of No and click Next
- To add a new weight, click New.
- Type a name for the new weight, click the drop-down arrow, then click a weight type and a size for bitgate weights. If the name of the weight matches the name of any fields in the feature classes, the field will be automatically associated with the weight. Click Ok.
- Click the dropdown under Field for each feature class you want to associate the weight with and select the Field. Only fields matching the weight type will be displayed.
- Repeat the previous two steps until all the network's weights have been defined.
- Click Next.
- If your geodatabase is stored in an ArcSDE geodatabase and you have a configuration keyword for the network stage, click Yes and choose the keyword from the dropdown menu. If not, skip to step 21
- Click Next.
- Review the options you specified for your new network. If you want to change something, you can go back through the wizard by clicking the Back button.
- When satisfied with your options, click Finish to create the new geometric network.
When building a geometric network from simple feature classes in an ArcSDE geodatabase, the input feature classes can't be versioned.
Network weights apply to all elements in the network. You can assign which weights are associated with which field on each feature class when you create the network feature class. You can add new weights after creating a geometric network; however, weights cannot be deleted after creating your geometric network. Learn more about the features of a geometric network.
At any time during the building process, you can abort by clicking Cancel on the Progress dialog box. When you abort building, the system deletes any network tables created and sets the database to the state before the building process started. If snapping was already complete, that change is permanent and won't be restored.
The geometric network builder can automatically adjust features in the input feature classes to correctly snap to connecting features. The default snapping tolerance is the x,y tolerance of the feature dataset's spatial reference. If snapping, you cannot use a value smaller than the default. Large snapping tolerances may cause unanticipated results. For best results, examine your data and provide a more appropriate tolerance. Snapping (geometry changes) cannot be undone.
If you specify that you want to store sources and sinks in a junction feature class, the AncillaryRole field will automatically be added to the feature class.
Geometric networks can be created from feature classes that support z-values. However, if one feature class in a geometric network supports z-values, then all the feature classes in the network must support them. When this condition is met, the network building process will create the orphan junction feature class as z aware and assign orphan junction features with a z-value that is equal to the coincident vertices to which it is connected. If a junction feature, whether orphan or user defined, is coincident with edge vertices that have different z-values, the junction feature will be flagged as a building error, and a record will be entered into the network build errors table. The z-values of features will have no bearing on how connectivity is determined during network building or editing.