Class Name: DRM Class Summary Item

Superclass - <Base Summary Item>

Subclasses

Definition

An instance of this DRM class is used as part of a summary of a transmittal's content to represent instances of a class (specified by the drm_class field value) that are used that transmittal.

<DRM Class Summary Items> are combined together to form a list of the classes that are present in a transmittal or part of a transmittal. Each such list has only one entry per class. However, it does not have to be a complete list of every class used, and it can include abstract classes.

Each <DRM Class Summary Item> can optionally have a list of <EDCS Use Summary Items> giving the classifications that are attached to instances of that class in the transmittal. Obviously this only makes sense for those classes that can have classification information.

Each <DRM Class Summary Item> can also have a list of <SRF Summary> instances giving the spatial reference frames defined in the transmittal by instances of that class. Obviously this only makes sense for those classes that contain spatial reference frame parameters.

Primary Page in DRM Diagram:

• 20

Secondary Pages in DRM Diagram:

Example

1. A summary of the classes used in an entire transmittal.

   

2. A summary of classes used in part of a transmittal. (See the FAQ list also).

   The geometry portion of the given <Environment Root> has the following layout.

   The geometry portion of the given <Environment Root> is therefore summarized as follows.

FAQs

Why is the <Union Of Primitive Geometry> in Example #2 a <DRM Class Summary Item> rather than a <Hierarchy Summary Item>?

This illustrates the possible use of <DRM Class Summary Item> if we were to use the <Hierarchy Summary Item> to show only the top level hierarchy (for some reason).

The data producer may decide, for a number of reasons, that it would be useful to summarize the hierarchy down to a certain level only, but that it's also useful to show that there are aggregates such as <Union Of Primitive Geometry> below that level - i.e., showing that they exist, rather than showing their position in the hierarchy, is what is of value.

Hey! The examples for <DRM Class Summary Item> show <Polygon> and <Vertex> instances as <DRM Class Summary Items>, but the examples for <Primitive Summary Item> show them as <Primitive Summary Items>! Isn't this ambiguous? What's going on?

This isn't ambiguous as the two classes (<DRM Class Summary Item> and <Primitive Summary Item> summarize different aspects of a transmittal. Therefore the same classes can (and will) quite legitimately be represented by both. So <Polygon> and <Vertex> can turn up as types of <DRM Class Summary Items>, to summarize their presence in the transmittal, and as <Primitive Summary Items>, to show common patterns of objects in which they are used.

Constraints

Composed of (two-way metadata)(inherited)

• zero or more <EDCS Use Summary Item> instances (notes)

Composed of (two-way metadata)

• zero or more <SRF Summary> instances

Component of (two-way)

• zero or more <Hierarchy Summary Item> instances (notes)
• zero or one <Transmittal Summary> instance (notes)

Inherited Field Elements

Notes

Composed of Notes

EDCS_Use_Summary_Item

 If present, the list of <EDCS Use Summary Item> components of
 a <Base Summary Item> instance summarize EDCS usage by instances
 of the class specified by drm_class that occur somewhere in
 the scope being summarized.

Component of Notes

Hierarchy_Summary_Item

 Here the given instance represents a class used in part of
 the given transmittal.

Transmittal_Summary

 Here the given instance represents a class used in the entire
 the given transmittal.

Fields Notes

drm_class

 This field indicates the DRM class of the object(s)
 represented by the given <Base Summary Item> instance.