The English Heritage Geophysical Survey Database is intended primarily to be a centralised index of all the geophysical work that the Archaeometry Branch has carried out during its existence. As such it records details of the location of the site (6 figure grid reference), purpose of survey (eg "to determine whether the scheduled area should be extended"), type of archaeology encountered or suspected (eg Roman temple), AML report title and a summary, abstracted from the report, of our findings. It is additionally intended that for recent work (1993 onwards), a hypertext copy of the full AML report should be included. It is hoped that records of archaeological geophysical surveys undertaken by other organisations will also be included once all Archaeometry Branch surveys have been added.

We intend to make the database accessible over the Internet in the hope of creating a useful resource for those concerned with archaeological geophysics in the UK and as an efficient way of fulfilling our public duty to make the results of our work available. This has raised the concern that treasure hunters might make use of such a facility to target sites likely to contain valuable buried artifacts with the intention of illegal excavation.

The present method of public dissemination for our work, is to make AML geophysical survey reports available on individual request, subject to the approval of the head of the Archaeometry Branch.

Possible Security Options

There are, essentially, two methods by which the database may be made publically available whilst addressing this issue: placing restrictions on access to it and/or limiting what information is available from it. The possible options, with their strengths and weaknesses are discussed below. It should be noted that a combination of the below may also be implemented.

1) Access Logging: The database server maintains a log of all computers accessing the database and precisely what information is requested. It is possible to specify computers that should be denied access or to grant access only to specified computers. For instance anonymous computers for which a registered internet name could not be determined could be denied access or access could be restricted to computers in specified networks (eg university campuses).

The advantage of this system is that it in no way limits the utility of the database for those that have access to it. The disadvantage is that banning access would probably have to be retrospective and, even if particular individuals were known to be abusing the system it may well not be possible to identify the computer accounts they used to gain access.

2) Restricting Grid References to 4 figures: This is already implemented in our test system and prevents location of the site to the nearest kilometre square. The problem is that it limits the utility of the database for queries where more precise positional information is required. Furthermore, often the name of the farm or address of the site is available in the report, or even in the report title, allowing more accurate location of the survey area. If access is denied to all information that might possibly provide more accurate locational information, the value of the database is severely compromised.

3) Deny Information About Sensitive Sites: Records on specified sites can be hidden from internet queries. The advantage here is that full information would be available about sites deemed not to be sensitive. The disadvantage is that it is often difficult to determine which sites are at risk and, the natural inclination to err on the side of safety might restrict the sites on which information was freely available, to a subset so small as to be useless.

4) Password Restriction on Access: It is possible to allow access only to registered user each of whom would be assigned a unique account and password. Prospective users would have to apply for access and The head of the Archaeometry Branch would vet the applications. This is closely analogous to the present system for dissemination of paper reports; the advantage is that only trusted individuals would be able to access the information. Disadvantages are the possible extra administration required to grant accounts and the lack of a public "shop window" as it would no longer be a publically accessible system.

5) A Two-Tier System based on the above: Perhaps option 4 could be implemented to give full access to those with a keen legitimate interest but a very limited interface could be provided for public access. Any positional queries would be limited to, say, "All sites within 10 Kilometres", and no grid references or report details would be available, only information on the geophysical techniques used. Furthermore, sensitive sites could be completely hidden as in 3.

Paul Linford
31st January 1995
Archaeometry Branch SCS/RPS