How to create a domain

A domain is a set of class names, IDs, or values that can be used in a certain data object. All ILWIS data objects have a domain. One domain can be used for several data objects.

To create a domain:

In the Create Domain dialog box which follows, you have to specify the type of domain you want to create:

When creating a Class or ID domain, the Domain Class/ID editor will be opened. In the Domain Class/ID editor, you can add the class names or the IDs that you want to use to the domain but you can also add class names or IDs to the domain later on, for instance during digitizing.

Note:

  • Within Names of classes or IDs, any characters may be used, except percentages %.
  • Within Codes of classes or IDs, any characters may be used, except colons : and percentages %.

When creating a Value domain, you can directly define in the Create Domain dialog box what values should be stored by the domain: specify a minimum and maximum value and a precision.

When creating a Bool domain, the Edit Bool domain dialog will be opened, where you can specify user-defined strings for True and False values.

Tip:

When working with maps of different years but of the same theme, or containing the same class names, IDs, or values, you are advised to create one domain for these maps and use this domain for all maps. It is not necessary that every class name, every ID or every value in your domain actually occurs in each map which uses that domain.

Representations:

Representations are linked to a domain. This means that when you use the same domain in several maps, these maps can easily be displayed in the same colors. ID domains do not have a representation.

When you create a new class domain, a new representation class is automatically created with the same name as the class domain. This representation will be used as the default representation for the domain and the representation will initially be filled with default colors.

One way to view and/or edit the representation of a class domain is:

For more information, see Representation Class editor and How to edit a representation.

When you create a new value domain, a representation value is not automatically created. Instead, system representation Pseudo will be linked to this domain as the default representation.

Two methods to create and/or edit your own representation for a value domain are:

or

For more information, see Representation Value/Gradual editor and How to create a representation.

See also: