Mapping Information Resources

Appendices

Contents

Appendix I: An Operational Framework for HEIRs
Appendix II: HEIRs in the UK: Summary descriptions (see separate file - c 0.7Mb)
Appendix III: The Z39.50 communications protocol
Appendix IV: Metadata standards
Appendix V: Example implementation of Dublin Core for an HEIR
Appendix VI: Thesauri & terminology control

Appendix I: An Operational Framework for HEIRs

1 The original version of this document was the first `deliverable', accepted by the HEIRNET Steering Group subject to review at the end of the project. Much of that review has occurred through drawing upon it while compiling the preceding report, so it is reproduced here with only minor editing and some preliminary comments.

2 The main lesson has been its usefulness in facilitating a relatively detached overview. Information about the historic environment can be viewed in the context of any of the framework's four elements. Looking at each aspect in its own terms provides an all-round view of the key issues for future development. This `360-degree' vision contains the higher-level objective of research and its associated duty of promoting understanding widely but retains a balance with other, for example social and economic, considerations. The approach is designed to bring information about the historic environment into the mainstream of developing policies for improved social access to heritage.

3 The comprehensive operational framework standing behind the processes of mapping and analysis has four components:

• the historic environment: its scope, extent, complexity, uses, and links with other environmental aspects
• the conservation process: its intrinsic awareness of time depth, and of the value of the past and a duty to the future; the sequence of its constituent activities, their various needs for skills and information, their outputs and links to other activities;
• information management: types and levels of information, technical standards for definition and curation, structures and systems for uses;
• organisational structures: their different kinds and purposes, needs for information, resource requirements and availability, and interconnections with other organisations.

4 The original paper was presented as a non-prescriptive preliminary analysis of information flows, informed by theoretical and practical issues. It sought to comprehend general matters affecting all information systems, generic matters concerned with various aspects of the environment, and specific matters distinctive of the historic environment. It was intended to help identify factors that govern the creation and use of information resources, and productive ways of ordering and linking disparate types, so as to improve interaction between information resources and their users.

The Historic Environment

5 The starting point is the physically indivisible environment. Qualifying it with `historic' characterises aspects altered by past human activity. Strictly, that activity is a process of the `natural' world because humanity is a biological phenomenon, a perception that underlies the concept of sustainability. It is also the product of a unique species whose earliest known traces in the material record date back perhaps half a million years. The historic aspect of the environment exists in those human-influenced alterations that remain discernible despite continuing natural and human processes of change. It exists only in present time, but the ability to recognise it as evidence for something that existed in the past is another uniquely human attribute.

6 The historic environment and what it represents can be reconstructed in time-lines of variable length and complexity and on several spatial scales. The linearity of time gives events sequence, underlies cause and effect, and throws light on varied human endeavour through comparison between different periods. Space has more flexibility: a widely accepted current view sees it analytically as a nested hierarchy of five descriptive levels:

• the overall historic environment
• the human-altered landscape and its patterns of settlement
• particular settlements and organised landscapes
• sites of evidence for past human activity and historic buildings in use
• artefacts and ecofacts.

7 Depending upon the type of evidence and the purpose of enquiry, surviving remains or the reconstructed entities they represent can be depicted spatially at various combinations of these five descriptive levels as

• specific points representing the location of where activity occurred
• lines denoting boundaries between spaces where different activities occurred
• polygons enclosing spaces co-terminous with definable units of activity.

8 The definition of the `historic environment' used here extends beyond the physical survivals themselves. It also includes information about them, whether they are still extant or were destroyed before the present day. This body of information has largely accumulated over the last half millennium, with an organised approach to collection evolving in public and private spheres during the last century. It has grown exponentially in the last thirty years as a consequence of new policies, deliberately securing lasting records of survivals before their destruction and recognising the importance of information in the conservation process. Its contents and formats reflect changing outlooks and methodologies for investigating the past: idiosyncratic antiquarianism has given way to description controlled through data standards and thesauri of meanings; philosophy of history and theoretical archaeology have burgeoned alongside (and often detached from) more pragmatic analysis of cause and effect.

9 All these developments have affected not only the nature of the information, but also how it is managed, which has become increasingly intricate as technological horizons have expanded. Another example of parallel expansion is the growth in the perceived width and extent of the historic environment, which is related to growth in appreciation of its potential uses.

The Conservation Process

10 Broadly defined, conserving the historic environment is a process involving several stages. This is emphasised by the way problems tend to arise when one stage is pursued without taking proper account of the others. Envisaging it as a self-sustaining set of activities within a context helps get things done in the right sequence.

11 The activities are awareness, management and feedback.

• Awareness comprises defining and agreeing what qualifies as `historic', locating surviving examples, identifying their significance, acquiring information about them, and storing it retrievably in maintained systems.
• Management deals with uses and change, including their documentation. It involves assessing proposals, balancing environmental, social and economic benefits, taking decisions about preservation, planning how to mitigate impacts, and devising technical strategies for maintenance.
• Feedback occurs as a result of these two sets of activities, during or afterwards, in one or both of two routes. The direct one improves understanding, and therefore continuing management, of what is being conserved, whether sites, buildings, areas, themes, subjects, times or places. The indirect one improves people's awareness, as individuals and in their communities, that the historic environment exists and has interest and value. That awareness helps give it due weight in the political process at local and national levels.

12 The context is the uses of the historic environment, which are the reasons why it is valued. Some of these uses are primary because they are directly related to the care and understanding of the survivals themselves and may be part of stages in the conservation process. Others are secondary or parallel, because the purposes for which they are used, however benignly, are different, requiring their own sets of skills in additions to a broad understanding of the survivals and / or the information about them. They are:

• academic (primary). Research and explanation seek direct understanding of past human activity, in the process modifying or adding to existing information. This can be done non-destructively by observation, such as of earthworks or buildings, or by recording in the process of destructive analysis. Research tends to attract an undifferentiated justification as the pursuit of knowledge being an absolute `good', but in practice priorities are often set by perceived potential or the availability of resources.
• cultural (secondary). Arts and tourism usually take survivals and information about them as found, then presenting them in interpreted forms. This can range from careful balances between authenticity and reconstruction to purposeful fictions that use historical information as a stepping stone towards largely imaginary creations.
• economic (parallel). Historic resources able to continue in original or alternative uses help meet the day-to-day needs of the present, whether it is a settlement in a long-preferred location or a building whose forms and appearance combine interest and flexible utility. The value attached to historic character can encourage economic use but is not always the overriding factor.
• educational (secondary / [primary]). Teaching and learning aim to pass on knowledge and understanding. Objectively they are `secondary' activities because the process does not directly change the source material, though it may stimulate curiosity that does have that effect. Subjectively, though, personal discovery is a kind of `primary' experience however it happens.
• social (secondary / [primary], parallel). If it is regarded as additional to the other four sets of uses (rather than embracing all of them) this may be the most complex and under-rated of them all. Its aim of using historical information to increase a general awareness of locality and environment puts it into the category of `parallel', but, like education, its element of personal discovery also mixes the `primary' and the `secondary'.

13 This overall view of historical conservation as a multi-staged process is relatively new, not consciously accepted by many who are mainly interested in particular stages. It is still insufficiently integrated with the management of information, which should be involved in all its stages. The consequences, uncertainty about the identity, nature and significance of a historic feature, can lead to inappropriate conservation strategies and interpretative presentations.

14 There are links between the conservation process and the other components in this framework. It is essential to understand something before deciding what to do with it: that may require appreciation at more than one spatial level or through analogies sought across time-periods. Awareness that there is a natural sequence of activities in the conservation process can help sustain an inheritance from the past by portraying it in terms of a responsibility to the future. Awareness of the context for that process can help view the aims and objectives of conservation through the minds of `customers' as well as resource managers. These are routes to the perspectives of the politicians and administrators who have the power to ensure adequate provision for the conservation of the historic environment in their organisational structures.

Information Management

15 Information management is at the core of this framework. It involves another set of inter-linked stages, creation, storage, dissemination and re-use. Most primary data is created locally, but the other stages could also be regional, national or international. They are rarely combined in one organisation, and users are at all levels. Information about the historic environment is dispersed around the world, in archives, libraries, and museums, and stored in different formats and media. Networks are important organisational facilitators of effective information flows; without them there are logistical obstacles for enquiries seeking to synthesise material from more than one source.

16 Creating information involves observation and recording, both of which are selective and purposeful. So that the basis of creation can be understood, an explicit brief should always relate the purpose of the work to the relevant stages of the conservation process, and define the relevant levels of spatial interest within the historic environment. A whole-farm survey as the basis for a management plan will produce information of a kind that is different from the detailed analysis of a part of a building to be repaired. Observation can never be objective: even recording `what is there' has its methodological preconceptions. Types of recording media offer a wide range of opportunities for capturing data that varies in width of focus, levels of precision, and potential for manipulation.

17 Information terminology also has to cope with often inexact meanings or usage for words like `data', `fact', `evidence', and `interpretation'. `Information' itself tends to be used as an umbrella term for anything recorded. `Data' may have replaced `facts' in the vocabulary, but their literal translation of `given' is deceptive: they have that status only as long as people share a common perception about what has actually been `captured'. This common perception may be strengthened (or shattered) as `data' is converted by the selective process of `interpretation' into `evidence' `for' something, giving it value or significance in the context of a solution to a problem.

18 The storage of information raises issues about effective structuring for multi-purpose retrieval, yet the options for structuring also depend upon the current state of information technology. With relational databases superseding flat-files, the scope for multi-variant analysis has greatly increased. In the same way, the ability to link databases with associated Geographical Information Systems has greatly enhanced the scope for analysing the historic environment as a set of nested spatial dimensions.

19 There is further potential in the `event - monument - archive' (EMA) data model. `Events' are single episodes of primary data collection over a discrete area of land, comprising one investigating technique and a unique entity in time and space (S Catney in SMR News, 7, January 1999, 1). They can spring from field or building survey, physical investigative intervention with the resource, or a management process. A `monument' is a perceived historical entity interpreted by assembling information derived from selected `events'. An `archive' is the unit of storage for information that can relate to single or multiple `events' and / or `monuments'. Distinguishing between these three elements helps clarify their interrelationships. It also usefully loosens up the connections between aspects of the historic environment and stages of the conservation process: `monuments' that are discrete assemblages of datasets have greater interpretative flexibility and more freedom from a priori preconceptions. The data model also highlights the need for working out consistent ways of retrieving the complex sets of information that comprise interpreted hierarchies of `monuments'. This requires organisations to develop consistent approaches to data collection and storage.

20 Dissemination and use involve a bilateral process, making systems and their contents passively accessible to enquirers, and taking information, usually selected and interpreted, out to people. Current studies of local records are highlighting some obstacles. Few of them fully cover all aspects or layers of the historic environment; they are weak on landscapes, settlement patterns and the built heritage. They were mostly created by, and their strength derives from, an organisational role that concentrates upon the land-use planning stages of the conservation process. A consequence can be poor communication with nonplanning users because their content lacks user-friendliness and is presented without an interpretative interface. Many local record systems are caught within a circle; they are poorly equipped to serve the wider social purposes for which they were originally envisaged, and equally ill-suited for building up the support that is essential for justifying the resources needed to develop that wider role.

21 Information management is the component of this framework best equipped to undertake its own enhancement. The WWW is the single most effective means for accessing, synthesising and publishing information on a global scale; any system that can respond to its technical requirements will find its capabilities greatly increased. The Web is evolving towards machine-driven information retrieval, wherein significant bodies of extant knowledge are offered up from existing databases and simultaneously searched by users remote from (and perhaps ignorant of) the originating system. This is being driven by the increasing use of communications protocols such as Z39.50, enabling a single user to make simultaneous queries of diverse, distributed, data resources, as long as the `target' databases conform to a given `profile'.

22 In this scenario, data creators have to provide appropriately organised and digitised material only once in order to allow comparable remote searching of diffuse data resources on distributed computer systems, by users casting their searches at their preferred geographical levels of county, region or nation. `Appropriately organised' means identifying key indexing fields that can be presented in standardised, machine-searchable ways, however the data is actually stored, whether centrally or locally, as index or detailed material.

23 At its simplest, this resource discovery metadata, or `data about data', cover three essential aspects,

• the nature of a body of information (such as that it is about stone tools)
• its location (such as that it is viewable online through the ADS homepage)
• the existence of similar information (such as in the British Museum).

Metadata can document everything the user needs to know in order to decide if the resource is usable, such as charges levied, copyright restrictions, and language. An emerging international and inter-disciplinary standard for resource-discovery metadata is provided by the Dublin Core, a metadata element set intended to facilitate discovery of electronic resources. It has simplicity, semantic inter-operability, international consensus, and extendibility, permitting cataloguers to use various standard `schemes' to describe each `Dublin core' field. Within a metadata scheme, thesauri and control of terminology are essential, so that users can know how search terms have been applied across their target collections. RCHME's actively updated Thesaurus of Monument Types: A Data Standard for Use in Archaeological and Architectural Records (1995) aims to standardise and correlate by listing terms hierarchically and indicating preferred terms in the case of synonyms.

24 A key task is the realistic application of these new concepts and techniques to the existing body of information and established approaches to its management. The Brief for this project asserts that “technology now exists to allow all digital resources to be linked within a networked environment to enable cross domain discovery. This will revolutionise access to information for research, management and education. Information management is making it easier to network, link together, or otherwise communicate between separate systems”. It draws attention to the potential of “the online catalogue being mounted on the Internet by the Archaeology Data Service ... which allow(s) any number of distributed databases to be searched from a single computer terminal located anywhere in the world.” However, such connections, like those cited as operational in Scotland and Wales, need to be carefully characterised so that there is clarity about what can be achieved. Making information available is not the same as using it, and users must be considered as well as systems.

25 As far as availability is concerned, an appropriate model might involve three levels of remote access, to:

• metadata that characterises the nature of a system's holdings in the form of types of data-field held, but cannot supply more specific information
• a metadata-based index listing all the records ordered by those fields
• detailed information behind that index, at least distinguishing what has and what has not been digitised

26 As far as the usability of what can be retrieved is concerned - whether by direct search or remotely - different users have different needs. From the viewpoint of information management it may be possible to characterise two broad classes:

• those that can be directly satisfied through standard interrogation of information in appropriate formats, perhaps supplemented by associated interpretative glossaries that are effectively part of the same system
• those, such as SCRAN, that will need to select information and re-present it before it can properly serve their purposes.

Organisational Structures

27 Organisations are considered here in relation to information systems, rather than for their broader roles in facilitating the understanding and uses of the historic environment. Detailed analysis of organisational roles and activities has not been undertaken as part of this project, except where it has been necessary in order to understand properly the functions of information management that an organisation actually fulfils.

28 A characteristic of the age is that organisational structures are changing more rapidly, and tending to become more complex. The advent of non-governmental organisations, and privatised or `out-sourced' services has blurred the distinction between `private' organisations, pursuing the specific interests of self-selected individuals, and `public' ones representing a wider social and political commitment. Commercially operating service providers, appointed to fulfil functions that were once solely in the public service domain, are now a significant element in the historic environment management sector. A corresponding growth has occurred in the part of the independent sector which seeks to monitor the performance of `private' and `public' organisations in relation to historic environment concerns and public amenity, often in a particular specialist or local context. Examples are environmental lobby and watchdog bodies like Friends of the Earth, SAVE Britain's Heritage, and community-based groups which have developed from local authority green audit focus groups.

29 Organisational territories range from the national to regional, to local authorities, parishes and neighbourhood communities. All require flexible access to high quality information about the historic environment, and compile and maintain it for their own purposes in more or less systematised ways.

30 Organisations participating in the various stages of the conservation process can operate in relation to any of the five contexts outlined above (Section 2.13) - academic, cultural, economic, educational or social - and in relation to a range of spatial and chronological scales. A hypothetical illustration might be the proposed adaptation of a redundant Victorian pumping station, significant for its design and technological interest, which coincidentally houses a colony of bats. A case like this will cut across conservation activities in multiple contexts, requiring information along an axis from general, to selective and specialised systems. These might include the water authority (as private owner), the relevant environment agency (as regulator of water quality), the heritage agency (to assess potential for listing / scheduling), the nature conservation agency (to assess impact on a protected species), the local authority planning and conservation sections, including the SMR (for record documentation and relevant permissions), the relevant Royal Commission on Ancient and Historical Monuments (to record documentation for the NMR and as a possible candidate for field survey), the regional or local museum (with an interest in the future care of in situ historic equipment and plant), national amenity groups (e.g. the CBA, the Victorian Society et alia for consultation on significance), special interest / academic groups (e.g. Association for Industrial Archaeology for specialist consultation); and last but not least the community group who wishes to see the building re-used as a field centre for local schools and the neighbours who consider it an eyesore.

31 The functions and interrelationships of organisations concerned with the historic environment form an elaborate network, and one of the most significant linkages through this network is the common need for access to information resources. An appropriate framework is therefore one based on the categorisation of organisations whose functions involve them in distinct ways with information systems for the historic environment. Four broad groupings of bodies are proposed and these form the basis for selective data gathering in the `mapping' process.

32 The core group of organisations managing key information systems for the historic environment are those who do so primarily as a service for others to use and whose activities include compiling material generated by themselves and by others (e.g. the Royal Commissions on Ancient and Historical Monuments). A related group within this core are those umbrella organisations concerned with standards, co-ordination and networking of information systems, independent of the specific needs of the historic environment (e.g. FISHEN, ADS, mda). A number of current initiatives and studies are relevant (such as the CBA's Publication User Needs Survey, Strategies for Digital Data, Accessing Scotland's Past, and Unlocking the Past) and provide useful signposts to future developments in this area

33 Closely allied to the core are conservation organisations with primary operational functions other than managing information systems. They use and generate information as part of their activities in the conservation process and as part of their duties to manage historic environment resources (including properties and collections). They either have a direct user / contributor relationship with the core group systems or manage their own bespoke systems. Many of these organisations make their information systems available for others to use but differ from those in the core group because this is not their sole or primary function.

34 Within this group of conservation organisations there are two sub-groups whose information systems are distinctly different in character and designed to operate at different scales. The first are historic environment conservation managing organisations, such as national heritage bodies, local authority historic environment services, National Parks, historic estate managers. These manage inclusive information systems which relate to a broad range of aspects of the historic environment in a defined geographical area. A key relationship to investigate in this sub-group is that between local and national record holding roles (see below, Section 5). The second group are historic collections and property managing organisations, e.g. for museum collections, including archaeological archives, historic places, cathedrals, churches, portable antiquities. These manage exclusive information systems which relate to defined archaeological or historic resources at a particular location. Some organisations perform both roles and manage separate information systems for each.

35 A third and separate group of organisations, often independent of public authorities, are those which compile and manage information systems for specialist studies and research topics. These organisations generally have systems designed for their own research purposes but often have a user / contributor relationship with the above groups. Some of these organisations depend on voluntary or part-time workers and are not well resourced.

36 The fourth category of HEIR organisations is that of secondary organisational users who derive HEIR information from systems managed by others. They influence opinion, policy and decision-making but without directly generating any feedback of fresh or revised information. The information systems which they maintain (if any) are primarily for administrative convenience and duplicate records held in other core or conservation information systems. These organisations include, for example, amenity groups, special interest groups, and public information organisations.

37 Finally there is an important group of organisations which facilitate access to heritage information held by others. They do not necessarily create or hold information themselves and include archaeology internet gateways, consortia for information exchange and networking, and EC programmes.

38 The operational framework in this project is principally concerned with the interaction between the first three categories of information managing organisation, and their potential relations with user and facilitator organisations. Large organisation with multiple roles commonly encompass more than one, or indeed most, of the categories of operational information system. The complexity of the larger picture across the UK is illustrated, for example, by the systems of the national heritage agencies, and of bodies such as the CBA which also manages an Internet gateway. Many HEIRs also have actual or potential links with other information sources and services outside the ambit of the historic environment. Established relations with other developed organisational networks in adjacent areas of activity (e.g. educational, environmental, geographical, arts and humanities) provide important interfaces for future development.

Appendix II: HEIRs in the UK: Summary descriptions (see separate file - c 0.7Mb)

Appendix III: The Z39.50 communications protocol

Z39.50 is a communications protocol developed over several years to enable the simultaneous query of diverse, distributed, data resources. Originally developed mainly in the United States and principally for library resources, Z39.50 has since become an international protocol (ISO 23950) used extensively within a range of communities.

Within the library community, Z39.50 is used to provide near-transparent access to collections data held in multiple databases, whether on a local level or more widely through services such as COPAC <http://cs6400.mcc.ac.uk/copac/> (which links the principal research libraries in the United Kingdom) or MELVYL <http://www.melvyl.ucop.edu/> (which links the libraries of the federated University of California and beyond).

Outside the traditional library sector, Z39.50 is becoming more widely implemented. The AHDS Gateway, physically based in London, uses Z39.50 to query five totally different databases containing information on archaeology (York), history (Colchester), the performing arts (Glasgow), the visual arts (Newcastle), and textual studies (Oxford). The databases describe different data types according to different cataloguing standards. They are driven by different database management software and run on a variety of hardware platforms. Nevertheless, despite these differences, the combination of Z39.50 and Dublin Core elements is sufficient to enable meaningful searches across the five sites.

In the geospatial community, adoption of Z39.50 has been most apparent in government-related initiatives such as the United States' Geospatial Clearinghouse network <http://fgdclearhs.er.usgs.gov/> and the Australian Spatial Data Directory <http://www.environment.gov.au/database/metadata/asdd/>. In both these government examples, numerous agencies offer Z39.50 access to their databases, either individually for visitors to agency- and subject-specific interfaces, or collectively through the clearinghouse URLs given above.

The Z39.50 protocol itself serves to enable communication between a client and one or more remote databases via the ubiquitous TCP/IP communications standard. Providing that both clients and `target' databases conform to one of a number of `profiles' for Z39.50, it is possible for a single user to query a large number of very different databases by means of a single user interface. Work underway at present on the Z39.50 Attribute Architecture is seeking to draw together a single list of elements or attributes from the various attribute sets that have grown up alongside the profile development process. When complete, this single Attribute Architecture will greatly simplify the task of utilising Z39.50 across, rather than merely within disciplinary groups (Miller 1999).

Perhaps the greatest strengths of Z39.50 are also the cause of it's perceived lack of deployment. Z39.50 is platform and application independent, allowing simultaneous querying of numerous remote databases. Therefore, when it works, the user may well not be aware that Z39.50 has been used, nor that the result set presented to them on screen has in reality been culled from a number of databases around the planet, each with their own internal data structure. A major benefit of Z39.50 is its neutrality. Z39.50 servers will effectively run on any hardware platform and on top of any standards-compliant DBMS. Importantly, collaborating partners in a Z39.50 project do not need to be using the same hardware, software or underlying data structure, so long as both can agree a common mapping into one or more Z39.50 `profiles'.

Z39.50 Terminology

attribute set a collection of `attributes' used both to declare any mapping between native database structures and to handle the query process. The `attribute set' may well include `use attributes' (field or element names), as well as attributes intended to describe how queries should be handled, such as `relation attributes' (<, =<, etc.), `completeness attributes' (whether or not a query maps to the entire contents of a field, or only to a subset), etc. Bib-1 is the most commonly utilised attribute set at present

client the application responsible for initiating a request which ultimately results in a Z39.50 brokered query

gateway an application capable of submitting user queries to a number of `targets' and able in some manner to translate, manipulate, and pool returning result sets

profile a structured statement of functions and the context of their use. Where applicable, this includes a declaration of those subsets of the broader Z39.50 standard and its relevant `profiles' which are relevant in this case

record syntax a `record syntax' is the set of definitions used by both `client' and `server' in exchanging information

schema a commonly understood representation of data held in the resource to be queried. Both client and server must understand the same schema

server the application responsible for responding to requests from a `client'. Often, this `server' is synonymous with the `target'

service Z39.50 comprises a number of `services' which make up the whole. Normal applications of Z39.50 will declare their requirement of one or more of these `services', such that any compliant application must support those which are required. These `services' include; Explain, Init, Present, Query, Retrieve, and Search

target the part of a `server' application responsible for handling Z39.50-based requests

Appendix IV: Metadata standards

The Dublin Core

The Dublin Core is a metadata element set intended to facilitate discovery of electronic resources. Originally conceived for author-generated description of Web resources, it has attracted the attention of formal resource description communities such as museums, libraries, government agencies, and commercial organizations.

The Dublin Core Workshop Series has gathered experts from the library world, the networking and digital library research communities, and a variety of content specialties in a series of invitational workshops. The building of an interdisciplinary, international consensus around a core element set is the central feature of the Dublin Core. The progress represents the emergent wisdom and collective experience of many stakeholders in the resource description arena. An open mailing list supports ongoing work.

The characteristics of the Dublin Core that distinguish it as a prominent candidate for description of electronic resources fall into several categories:

Simplicity

The Dublin Core is intended to be usable by non-cataloguers as well as resource description specialists. Most of the elements have a commonly understood semantics of roughly the complexity of a library catalogue card.

Semantic Interoperability

In the Internet Commons, disparate description models interfere with the ability to search across discipline boundaries. Promoting a commonly understood set of descriptors that helps to unify other data content standards increases the possibility of semantic interoperability across disciplines.

International Consensus

Recognition of the international scope of resource discovery on the Web is critical to the development of effective discovery infrastructure. The Dublin Core benefits from active participation and promotion in some 20 countries in North America, Europe, Australia, and Asia.

Extensibility

The Dublin Core provides an economical alternative to more elaborate description models such as the full MARC cataloguing of the library world. Additionally, it includes sufficient flexibility and extensibility to encode the structure and more elaborate semantics inherent in richer description standards

Metadata Modularity on the Web

The diversity of metadata needs on the Web requires an infrastructure that supports the coexistence of complementary, independently maintained metadata packages. The World Wide Web Consortium (W3C) has begun implementing an architecture for metadata for the Web. The Resource Description Framework, or RDF, is designed to support the many different metadata needs of vendors and information providers. Representatives of the Dublin Core effort are actively involved in the development of this architecture, bringing the digital library perspective to bear on this important component of the Web infrastructure.

The Dublin Core itself consists of fifteen core elements, each of which may be further extended by the use of SCHEME and TYPE qualifiers.

Federal Geographic Data Committee (FGDC) Digital Geospatial Metadata

The FGDC metadata system is much more complex than the Dublin Core. The FGDC is primarily concerned with spatial information, thus its metadata system contains fields to identify the data set, data quality, data format, location, vector or raster nature of data, the coordinate system used to georeference the data, attribute information for spatial coordinates, how to cite the data set, temporal coverage of data set, the agency/individual which created the data, and who to contact for more information.

Global Change Master Directory (GCMD) Directory Interchange Format (DIF)

DIF is designed for the exchange of information relating to global environment change. It is thus particularly useful for climatologists, oceanographers, palynologists, palaeo-geographers, environmental archaeologists, etc. There are a total of 33 fields in the DIF system, but only 7 of these are required. Fields record information such as the project title, investigator's name, discipline (e.g. 'archaeology'), context of data, kinds of measurements included (e.g. ice cores), keywords, temporal and spatial coverages, resolution, quality, how to access information, restrictions on use of information, storage medium, bibliographic references, and a short text summary. Also recorded in the DIF system is information about the metadata itself. For example, the name of the person who authored the metadata, revision dates, and upcoming review dates can be incorporated.

The HEIRNET consultancy has identified the considerable number of information systems concerned with the historic environment. Whilst many are maintained by statutory bodies there is also a large and growing number of systems in private hands. It is recommended that it would be useful to establish and maintain a database of HEIRs in order that the growth of information systems can be monitored and future duplication minimized. Such a database would present index data describing the content of each HEIR so that a user would be enabled to locate HEIRs of interest i.e. resource discovery metadata. Such a database would therefore be an invaluable tool for those seeking to discover resources appropriate to research projects.

In order to maximize the value of a database of HEIRs so that it would be of application outside the immediate historic environment discipline, and to encourage interoperability with other systems, it is essential that it should follow international metadata standards. The Dublin Core provides an international cross-domain resource discovery metadata standard.

Dublin Core elements may be optionally applied, extended with implementation-specific TYPE attributes, and repeated as necessary when describing any given resource. The Dublin Core elements map extremely well to the information which the HEIRNET consultancy has collected about HEIRs (See Appendix 1) and it would be relatively straightforward to implement these records within searchable database, such as the ADS catalogue ArchSearch. The only class of information collected which is not adequately described within the Dublin Core is that of audience, i.e. what is the intended user group for an information resource, and would mitigation be required to make it accessible to another group. This is a problem that has been recognized by other bodies. The Gateway to Educational Materials (GEM) in the US (http://www.thegateway.org/) has added a sixteenth element, which is used to denote which school Grade a resource is for, as well as either Adult, Continuing, or Higher Education. The Education Network Australia (EdNA) (http://www.edna.edu.au/EdNA/home.html) adopts a similar solution, with a field for Educational Sector, options for which are schools, vocational education, adult and community education, higher education, and non-specific educational sector. See http://flare.dstc.edu.au/edna/help/help-edna.html for their controlled list.

The following fields illustrate a notional implementation of Dublin Core within the ADS catalogue to provide a record for the mixed media resource, Images of England:

Art and Architecture Thesaurus - The Getty Information Institute produced this thesaurus in 1990 and has recently made it searchable over the World Wide Web. It provides for standardised description of material culture, architecture, and art in the Western World from prehistory to the present. Vocabulary is controlled through a hierarchical structure of broader/narrower terms, synonym control, and other tools.

British Archaeological Thesaurus - Written by Cherry Lavell and published by the Council for British Archaeology in 1989, this was the earliest thesaurus for British archaeology. It remains a useful companion to back issues of the British and Irish Archaeological Bibliography (and its predecessors, British Archaeological Bibliography and British Archaeological Abstracts), but is now out-of-print.

British Museum Materials Thesaurus - Released and published in 1997 at the same time as the MDA Archaeological Object Thesaurus, this thesaurus was edited by Tanya Szrajber and compiled by the museum Collections Data Management Section. This thesaurus was a response to their need to document collections from any time period around the world, and it provides a good resource for terminology control of organic, inorganic, and processed materials.

Core Data Index to Historic Buildings and Monuments of the Architectural Heritage - Developed by the Council of Europe for architectural recording.

European Bronze Age Monuments: A Multi-lingual Glossary of Archaeological Terminology - Created in 1995 by a multinational working party for the Council of Europe, this multilingual thesaurus pilot project is designed to assist in the recording of Bronze Age archaeological sites and monuments in Danish, Dutch, English, and French. Though the terms within the glossary are listed in all four of these languages, the glossary itself is currently available only in English and French. When this glossary makes its public debut, it should be a very helpful resource for prehistorians throughout Europe.

Guide to the Description of Architectural Drawings - Published in 1997, this guide provides a general introduction to the principles of documenting architectural materials with recommendations for both digital and manual systems. Developed by the Getty Information Institute and partners.

Handbook of Standards; Documenting African Collections - Published in 1998 by ICOM, this resource is published in both English and French. It provides guidance on the minimum amount of documentation required for museums curating objects from Africa. All museum disciplines are covered from humanities subjects to natural science subjects.

Index Record for Industrial Sites - Published by the Association for Industrial Archaeology in 1993 this is a handbook for recording evidence about industrial heritage. The booklet includes recording forms and a variety of terminology lists.

International Core Data Standard for Archaeological Sites and Monuments (Draft) - Produced in 1995 by CIDOC, the International Documentation Committee of the International Council of Museums, this document guides the user in documenting archaeological sites and monuments. The goal of this standard is to facilitate international exchange of information by encouraging standardised approaches to database structure. Useful information about naming, describing, cross-referencing, and spatially referencing sites and monuments is provided. Working examples from Denmark, England, France, and the Netherlands are provided. Contributors come from these countries and Albania, Canada, Poland, Romania, Russia, and the United States.

International Guidelines for Museum Object Information: CIDOC Information Categories - CIDOC, the International Documentation Committee of the International Council of Museums has developed these guidelines about what information should be recorded for museum objects, how it should be recorded, and the terminology with which this information should be recorded. This standard is particularly useful for archaeologists working in a museums setting.

MIDAS: A Manual and Data Standard for Monument Inventories - Developed by RCHME in 1998 to assist in the creation of monument inventories such as Sites and Monuments Records (SMRs). Includes recommendations for terminology control for archaeological evidence in England, and is an indispensable resource for archaeologists working in England.

Multilingual Egyptological Thesaurus - The International Association of Egyptologists (IAE), Comité International pour l'Égyptologie (CIPEG) and the International Council of Museums (ICOM) joined forces to create this thesaurus useful for anyone working on or interested in Egyptology. This thesaurus covers a variety of topics including present location, provenance, dating, material, preservation, description, text, divine names, and royal names. Includes entries in English, French, and German. Arabic, Italian, and Spanish additions are planned.

MDA Archaeological Objects Thesaurus - The Museums Documentation Association has released this thesaurus of object and artefact names in conjunction with the Royal Commission on the Historical Monuments of England and English Heritage. The goal of this thesaurus is to encourage access to, and reuse of, collections, archives and record systems, and to facilitate cooperation and data exchange between all individuals and institutions involved in the retrieval, research and curation of archaeological objects.

National Heritage Reference Dataset (NHRD) (Draft) Currently being developed by FISHEN - the Forum on Information Standards in Heritage (England) - this resource is intended for use with MIDAS. A variety of termlists and scope notes have been developed for high-level terminology control for things such as scientific dating techniques used in archaeology.

NMR/SMR Maritime Type Standards - Useful standard for recording coastal and underwater archaeology sites.

Recording England's Past: A Data Standard for the Extended National Archaeological Record - Produced by the Royal Commission on the Historical Monuments of England and the Association of County Archaeological Officers (ACAO, now the Association of Local Government Archaeological Officers, ALGAO) in 1993, this standard is a data dictionary specifically designed for recording information within England's Sites and Monuments Records. It has been superseded by MIDAS.

Recording Historic Buildings: A Descriptive Specification - Currently in its third edition, this standard was developed by RCHME. Besides providing a short overview to field recording practice, this document provides a useful summary of architectural drawing conventions. There is little discussion of digital recording of historic buildings, but many of the recommendations made are also relevant for those using CAD packages.

Rules for the Construction of Personal, Place and Corporate Names - The National Council on Archives' 1997 guide to the recording of name information in archives. These rules include guidance on the use of non-current place names, and other issues of relevance to the archaeological community. Available from http://www.hmc.gov.uk/nca/title.htm.

Scottish Institute of Maritime Studies Thesaurus of Vessel Types (draft) Shipwreck Identification Thesaurus by A. M. Elkerton

Simple Subject Headings - Designed by the MDA for use in small museums, this tool helps control terminology used to classify museum collections. Four broad categories are included: community life, domestic and family life, personal life, and working life. This is a simplified subset of the MDA's Social History and Industrial Classification.

Social History and Industrial Classification, 2nd edition (SHIC2) - The MDA's standard for classifying the subject matter of museum collections. A simple sub-set of SHIC2 is provided by the less formal Simple Subject Headings system, although SHIC2 should be used where possible.

SPECTRUM: The UK Documentation Standard - Created by the MDA in 1994 as a standard for documenting museum collections, its use is required for registration with the Museum and Galleries Commission. The MDA provides a team of subject specialists, including an archaeologist, who are available to advise about the use of SPECTRUM.

Thesaurus of Archaeological Site Types - This 1992 thesaurus has been superseded by the RCHME Thesaurus of Monument Types.

Thesaurus of Architectural Terms - This 1989 thesaurus has been superseded by the RCHME Thesaurus of Monument Types.

Thesaurus of Building Materials: A Standard for Use in Architectural and Archaeological Records - An unpublished standard from the Royal Commission on the Historical Monuments of England, this thesaurus deals explicitly with the stuff of which buildings are composed: animal, vegetable, or mineral. Like the Thesaurus of Monument Types, terms are organised hierarchically and terminology control is provided. Users can nominate terms to be included in this thesaurus by returning a form within the thesaurus to the English Heritage Data Standards Unit.

Thesaurus for Cataloguing Military Collections - Developed by the National Army Museum.

TGN - The Thesaurus of Geographic Names is a project of the Getty Information Institute, aiming to create a powerful resource holding information on names of inhabited places, regions and geographic features both now and in the past. Importantly, TGN is holding these names within a hierarchy, such that it may be determined that a town lies within a country, that country within a continent, etc.

Thesaurus of Monument Types: A Data Standard for Use in Archaeological and Architectural Records - Produced by the Royal Commission on the Historical Monuments of England (RCHME) in 1995, this is a standard for use with both archaeological and architectural information. This thesaurus is actively updated by the Data Standards Unit at English Heritage. The purpose of this thesaurus is to standardise the terms used to describe archaeological sites or standing buildings by, for example, listing terms hierarchically and relating the levels of this hierarchy to one another or indicating preferred terms in the case of synonyms. For example, the hierarchical structure means that RELIGIOUS monuments include the subset of MONASTERYs and that there is a further sub-division into BENEDICTINE MONASTERY or CISTERCIAN MONASTERY depending on the particular monument being described. Synonyms are dealt with by pointing the user to a preferred term (e.g. for 'tribunal' use COURT HOUSE). This is one of the most widely used documentation standards in UK archaeology, and is a useful source of subject terms.

Union List of Artist Names - Another useful standard from the Getty Information Institute available online, the ULAN offers a way to control the recoding of names for over 100,000 artists and architects. Although of limited use to archaeologists, some prehistoric and medieval artists are included. This standard is very helpful for those involved in the recording of standing buildings.

wordHOARD - The MDA wordHOARD site provides connections to all manner of standards, including details for such things as SPECIES 2000, the Smithsonian Institution's World List of Insect Families, and the Vascular Plant Families and Genera databases from the Royal Botanic Gardens.

Many organisations are also likely to have internal thesauri and authority lists of potential use to the wider community. For example, the British Museum maintains thesauri for manufactured materials, manufacturing techniques, material culture/period, form and design. The Museum of London maintains authority lists for periods (e.g. prehistoric, Roman, medieval, post-medieval, and later) which are linked to the Art and Architecture Thesaurus where appropriate. The English Heritage Data Standards Unit has a wide range of internal thesauri and word lists, which the Unit reviews and develops, e.g. evidence and maritime thesauri; county, unitary authority, district and parish lists; condition schemes; associated roles (people and organisations) lists etc.