A quick tour of subtypes
Subtypes are a subset of features in a feature class, or objects in a table, that share the same attributes. They are used as a method to categorize your data.
Subtypes allow you to do the following:
- Increase the performance of the geodatabase by representing a variety of real-world objects as a subset of features in a given feature class instead of creating new feature classes for each object. For example, the streets in a streets feature class could be categorized into three subtypes: local streets, collector streets, and arterial streets.
- Set a default value that will automatically apply when creating new features. For example, a local street subtype could be created and defined so that whenever this type of street is added to the feature class, its speed limit attribute is automatically set to 35 miles per hour.
- Apply coded or ranged domains to features, enabling you to constrain input information to a valid set of values. For example, in a water distribution network, the subtype water mains could have a coded domain for building materials restricting them to be made of cast iron, ductile iron, or copper.
between other subtypes and feature classes to maintain the integrity of a network. For example, in a water network, a hydrant can connect to a hydrant lateral but not to a service lateral.Note:
This and the following points are available with ArcInfo and ArcEditor only.
- Create topology rules between other subtypes and feature classes residing in a topology. For example, you could make a requirement that street features have to be connected to other street features at both ends, except in the case of streets belonging to the cul-de-sac or dead-end subtypes.
- Develop relationship rules between other subtypes, tables, and feature classes.For example, in an electrical network, you could create a relationship rule between subtypes describing that steel poles support class A transformers, while wooden poles support class B transformers.
- Create customized rules between features using written code.
Subtypes can be created in two ways:
- Use the context menu in the Catalog tree.
- Employ geoprocessing using the Subtypes toolset.