Network analysis > Analyzing geometric networks > Creating and managing geometric networks
Managing a geometric network(ArcInfo and ArcEditor only) |
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Release 9.2
Last modified February 1, 2008 |
Print all topics in : "Creating and managing geometric networks" |
NOTE: Although geometric networks can be both created and edited in ArcInfo and ArcEditor, they are read-only in ArcView.
You can manage geometric networks using ArcCatalog. Unlike most items that appear in ArcCatalog, the geometric network does not represent a single entity, such as a table, shapefile, or feature class. A geometric network is actually an association among several feature classes and is represented by several tables in the database. Managing a geometric network is different from managing other items in ArcCatalog.
Managing the geometric network
Some of the standard operations on the geometric network work the same way as other items in ArcCatalog. A geometric network can be copied or deleted. Copying a geometric network persists the network connectivity and feature classes. Deleting a geometric network also deletes the network schema and causes the network feature classes to revert to simple feature classes.
Geometric networks can be copied in two ways: by copying the feature dataset containing the geometric network or by copying the geometric network itself. If the geometric network is copied, the target feature dataset must have the same spatial reference and extent as the source feature dataset.
Geometric networks can be deleted by deleting the containing feature dataset, which will remove the geometric network and any other object stored in the feature dataset, or by deleting the geometric network itself, which will leave the feature dataset and its containing objects intact.
Once your geometric network is deleted, the following changes occur:
- The network feature classes revert to simple feature classes. Edge feature classes become line feature classes, and junction feature classes become point feature classes.
- The geometric and logical network tables are deleted
- The orphan junction class is deleted. For this reason it is not recommended that the orphan junction class be used to store additional information. Before deleting the geometric network, the orphan junction features can be copied or exported to a new feature class, if the features need to be retained.
- Connectivity rules and weights are deleted
- The enabled and ancillary role fields are not removed from feature classes. These fields and the values contained within them may be re-used if the geometric network is recreated
- Any snapping performed on the network during building will not be undone. If the geometric network is recreated you do not need to specify snapping again, unless a larger snapping tolerance is required
Any of the following will require you to delete and then recreate your geometric network:
- You need to add a new populated feature class to the network
- You need to add or remove a weight from the network
- The snapping tolerance was too small on the previous build
- You need to change a feature class from a simple edge to a complex edge or vice versa
- You need to add a specific junction feature class as a source or sink, or remove it's ancillary role
- You want to rename the geometric network
Managing network feature classes
Managing network feature classes is more restrictive than managing simple feature classes. While a network feature class's alias can be changed, its name cannot. Deleting a network feature class is also more difficult than deleting simple feature classes. To delete the network feature class, you must first delete the geometric network; this action converts the network feature class to a simple feature class that can then be deleted. The alternative is to delete the entire feature dataset, which deletes the network and all the feature classes.
Schema locking
An exclusive lock is required to modify a geometric network's connectivity rules, add a feature class to the geometric network or delete a geometric network. An exclusive lock can only be acquired for a geometric network if the feature classes that participate in the network can also be locked. Therefore, if a user has an exclusive or shared lock on any of the feature classes in a geometric network, then the properties of the geometric network can't be edited.
Learn more about exclusive locks and schema locking