of Representation/Point of View
This area covers categories of information intrinsic to
architectural documents such as their physical characteristics, their
origin, and their purpose. Its definition reflects the fact that a
catalogue entry normally corresponds to a physical group or item in
its current state.
Levels of Cataloguing
The Guide defines three levels of cataloging, which may be
characterized briefly as follows: 
- Group: An aggregate of items that share a common history.
Groups range in scope from the several thousand items that may
represent the archives of an architect or agency, to a handful of
surviving drawings for a single design.
- Volume: Any bound volume (e.g., album or sketchbook)
containing pages or folios.
- Item: A sheet or support, including any attached overlays.
Objects such as three-dimensional models, coins, etc. may also be
A fuller discussion of these levels and their characteristics
appears in Document Classification.
The first step in cataloguing is to determine which of these
levels is appropriate, a decision that may be based on several
factors. In general, documents that exist alone or have individual
significance should be described at the item level. Documents that
were compiled consciously in a volume may be described collectively
as a volume. Documents that were made or received and retained as a
group because of common purpose or origin and that can be described
meaningfully in the aggregate may be catalogued at the group level.
Choice of level may also be influenced by the resources and
priorities of the institution and a projection of research needs.
Traditionally museums have collected individual architectural
documents with artistic significance and thus have stressed the
unique aspects of items. On the other hand, archives, which typically
acquire documents in natural, organic groupings, often (although not
always) describe at the group level. Whatever the approach to
cataloguing, it is important to recognize the value of both
traditions: to capture both the qualities of the individual object
and the aggregate histories of bodies of architectural documents.
Records may be made at more than one level: a general record for a
group and specific records for volumes or items within it, or a
general record for a sketchbook with separate descriptions for each
page or folio. The relationship between the part described and the
whole to which it belongs must always be expressed.
Uniform Record Format for All Levels of Cataloguing
There may seem to be a justification for treating groups, volumes,
and items differently, since some concepts seem specific to certain
levels, such as administrative origin for groups,
compiler for volumes (albums), and maker for single
items. This approach, however,
requires relating three different types of record formats to one
another and thus leads to a highly complex data structure, with
identical information being put in different data fields, depending
on the level. This is not only confusing to cataloguers, but presents
retrieval difficulties as well. Thus the Guide recommends the
same data structure for all levels of description.
Retrieval Considerations Particular to Group-level Cataloguing
The relationships of individual volumes and items to groups have
implications for retrieval. The most basic way of allowing for
retrieval by group attributes is to include the most salient
information about a group in the entries made for each item that
forms a part of it. This is, however, a very labor-intensive way of
proceeding, because individual pieces of information common to all
members of the group must be duplicated in the respective entries. In
the case of archival records, repositories may make group
descriptions at more than one level: for example, an entry for an
entire record group (representing a number of different series
deriving from a single originator), an entry for each series within
that record group, and an entry for every project file within each
series. These descending levels of entry may, depending on the data
structure employed, contain either duplicate information from the
larger group record (the "parent''), or a cross-reference to it.
Another consideration for retrieval is that a group-level entry
describes the material collectively and thus will consist of a
general analysis of the qualities and characteristics of the group as
a whole. In contrast, a catalogue entry for a single item can analyze
it specifically and may, in theory, describe virtually every aspect
of it. Of course, because of practical limitations this is never
actually done, but because there is a one-to-one relationship between
the entry and the item, enumeration of a limited, specific set of
characteristics is the model of single-item cataloguing.
In contrast, group cataloguing entries focus on describing
coherent, collective bodies of documents that may consist of many
items. The description thus emphasizes the characteristics of the
group as a whole instead of the distinctive qualities of each item.
The group description also may highlight unique, distinctive, or
important objects or characteristics that either are or are not
present in the group as a whole. Likewise, characteristics included
in the group as a whole may or may not be found in a specific item.
In an item entry, if the field for Subject/Built
Work Type (by function/form) says lighthouse, it means
that such a building is depicted (or thought to be depicted) on the
item. If the same happens in a group entry, however, it may or may
not mean that all the items in the group have lighthouses as
subjects. Most likely only some of the items do, but the cataloguer
has decided that the theme is prominent enough to be mentioned.
Group-level description summarizes the qualities and
characteristics of the whole; however, this fact may not be apparent
to users. A researcher may read an entry and, not finding what he or
she is looking for, miss relevant material. A careful analytical
description of a group, if thoughtfully considered, may reduce this
possibility. It is for this reason that group-level cataloguing is
most suitable to homogeneous groups of materials.