Author: Iris Meshulam
Co-authors: David Gabai Mikko Louhivuori

GIS implementation in Israel Antiquities Authority

General

The Israel Antiquities Authority (IAA) is the sole organization in Israel authorized by law to declare and maintain archaeological sites. The IAA was established in 1990 in order to preserve the cultural heritage of Israel by assuming responsibility for all land-based and marine antiquities. The IAA is responsible for implementing the 1978 Antiquities Law.

The Minister of Education is responsible for the Authority, which is supervised by a board of directors headed by a member of the Israel Academy of Sciences. The Survey of Israel (SOI) is the principal mapping agency in Israel, responsible for everything related to mapping in Israel, maintaining the nationwide geodetic control net and performing topographic, thematic, and cadastral mapping.

In 1989 the SOI began the construction of a comprehensive Geographic Information System (GIS). This system, which comprises the basis for a nationwide public GIS, stores the Israel's official geographic data, both cadastral and topographic. The National Land Registration Office (NLRO) is authorized by law to register and maintain land rights. NLRO is also the official arbitrator and approver of land transactions.

Israel is one of the few countries in the world that has a state agreement about land rights. The land registration process is based on official measurements, mapping and legal official and public investigation of claims to ownership. This process has a direct economic implication on the value of the land.

The IAA along with the SOI and NLRO are three of several organizations that take part in the registration process and therefore have an impact on land value.

Because of the rapid growth in urban development and the growing need for housing land registration records are constantly changing. This compels all the relevant organizations to regularly update their land relate information.

IAA Overview

The IAA has several functions: primarily the declaration, supervision, surveys and excavation of archaeological sites (all these will be discussed in greater detail later on).

In order to provide accurate information on archaeological sites within the state of Israel IAA must cooperate with the SOI, the NLRO and other governmental or non-governmental planning offices. This involves regular exchange and update of the rapidly growing databases in each of these organizations.

In the past, all of the above functions were carried out using traditional techniques:

Archaeological sites were presented using pencil, printed maps and rulers.
The accuracy of site coordinates was based only on the archaeologist's map reading skills.
Cadastral data was manually extracted from printed maps.
Accumulating archaeological data was stored in Alpha Numeric (AN) Database and paper documents.

Some of the problems rising from using such traditional techniques were:

Inaccurate and laborious manual work.
Basic Alpha Numeric (AN) data was stored separately from geographic data because of the limitations of the AN database.
Slow processing time and inadequate response time to requests from the public.

During this period the IAA also had difficulties in managing the large volume of data and the growing number of users. IAA was unable to:

Present AN data integrated with geographic data from several sources.
Keep up with the rapid changes in the database both within and outside the IAA.
Make spatial queries.
Integrate and process advanced geographic technologies like GPS readings, digitized maps, and so on.
Present accurate geographic data.

In 1995 the IAA was forced to move on to develop a system that could manage the many archaeological sites in Israel both efficiently and accurately. During that time, the IAA purchased some Differential Global Positioning System (DGPS) receivers for field use and began to collect satellite based positioning data on archaeological sites on a daily basis. By that time it was clear that GIS technology was the most suitable answer to the needs of Archaeological Sites Management, and in early 1996 the IAA began to develop the prototype of it's own GIS.

The IAA GIS project

Objectives

The main objectives of the new GIS project were:

To develop a computer based Archaeological Site Management system.
To integrate the system with the IAA's existing database.

Technology

Of the many GIS software packages available at that time, IAA chose the PC version of ArcView for the following reasons:

It met most of the functional needs (database management, spatial operations, statistics, ODBC ability).
It was already used by a number of governmental agencies and local planning authorities; this facilitated the sharing of regional geographic information (using the "work of others" accelerated some initial stages in the project).

For a Global Positioning System, the IAA decided to work with the Trimble ProXR because:

It has eight digits accuracy.
The software accurately converts UTM data to Israel Old coordinate system.
The software is able to export data into many formats.

Building the Project

General

At first IAA gained some experience on:

Hardware and software capabilities required for building the GIS Database.
Digital regional geographic information available in Israel.
Identifying the different needs from the GIS database.
Refining and evaluating the time and effort required for using the application.

Digital geographic information was rare and expensive. It still is. The IAA has had no alternative but to rely on the field data from the DGPS to locate archaeological remains. The DGPS has become the IAA's chief geographic data collector.

Database System Architecture

The IAA is currently using five different database systems from which the distinct layers of the GIS are constructed (fig.1). These can be grouped into two sections:

Databases within the organization.
Databases obtained from other organizations.

Database within the organization and their layers

The IAA central alphanumeric Database (Oracle RDBMS)

Archaeological sites layer: Vector polygonal built of two pairs of coordinates. During the last two years these coordinate pairs have been collected with DGPS.
License of Excavations and Surveys layer: Vector polygonal layer built of pairs of coordinates collected using DGPS.

DGPS Database (8-digit accuracy)

Survey data layer -Vector data collected with DGPS (Point, Line, Polygon).

Survey maps layer - Vector subset of the latter layer that contains centroids of archaeological clusters.

Supervision data layer - Vector data collected with DGPS from daily archaeological supervision activity, such as test trenches, or from sites damaged during building activities (Point, Line, Polygon).

Excavation Database

Finds layer - Vector data based on alphanumeric data collected during excavations and representing the findings and their exact location.
Excavation drawings layer - vector data, based on world-registered drawings and sections of every object in the excavation (DGPS & Distomat accuracy).

Database Obtained from Other Organizations

National Survey of Israel - (ArcInfo, Oracle)
Background map layer - Raster maps (1:50,000 scale).
Cadastral layer - Vector Polygonal layer (1:2,500 scale).

Other Government and Local Planning (Cad, SHP, MIF) Background map layers -(linear or polygonal) mostly contains a closer look on the developed area (1:250 or 1:500 scale).

In order to use these heterogeneous sources of data the information is first carefully checked and then converted to the IAA working environment: non-projected Israel Old coordinate system (Cassini) and Esri based software format. Unfortunately, because the main database is not fully integrated with the geographic one, some of these checking/converting processes must still be conducted manually. In the future, however, a centralized geographic database will solve this problem.

The IAA Main Implementation of the Geographic Information System

The IAA is using the GIS mainly for managing archaeological resources in the following areas:

Declaration of Antiquities Sites

Any land property containing antiquities is declared an "Antiquities Site". This status means that the land is under the special protection of the law.

An official government publication created by the IAA lists all declarations of antiquities sites. This gazette gives the exact coordinates for the site and some descriptive information about the archaeological remains. IAA also gives it to the National Land Registration Office as a cadastral list. This process is absolutely necessary in order to protect the archaeological sites from destruction by land development. In the same time the publication gives the public direct access to data about land properties containing archaeological remains.

Over the years the IAA has collected site locations as two pairs of coordinates representing a rectangle or a centroid representing the highest concentration of archaeological items at the site. Declared archaeological sites are represented by a rectangle (envelope) delimiting the estimated boundaries of the site. There was no way to collect or present the real boundaries of the site.

In the past it was not technically possible to examine the location of the site simultaneously with relevant information about it, such as DGPS and cadastral data. This lack of functionality was a possible cause for data errors in the main database.

The use of the GIS enables the IAA to integrate all relevant data in order to present up-to-date maps of archaeological sites, their location and description and so to support more efficiently the declaration process (fig.2).

The new technology also provides the IAA with polygons representing the archaeological site much more accurately than the traditional rectangle (fig.3).

The use of GIS in the IAA has brought many improvements:

Better quality control on the data entered to the main databases.
The system is less prone to human errors when most of the data is digital.
Higher accuracy due to the integration of the DGPS.
Much shorter data processing time.

Preservation and Supervision of Antiquities Sites

Regional supervisory districts and the marine archaeological unit carry out preservation work. Supervisors monitor construction and development plans, enforce the law and try to prevent any damage to archaeological sites.

The IAA has been in charge of enforcing the 1978 antiquities law for the past 10 years. During this time the IAA has supervised huge number of massive land development projects and documented the archaeological remains found.

After the construction work it was difficult to know where exactly the site has been. Due to the use of not so detailed (1:50,000) maps and the complete change in the landscape, it was often difficult and occasionally impossible to find the exact location of the archaeological site. It was equally difficult to produce a report on the location of the finds for the land developer and therefore obligated the IAA to follow the work in the areas under development.

GIS greatly helps the IAA to cooperate with land developers and constructors. IAA supervisors can now map the exact location of the antiquities in a specified area. This prevents much of the potential damage and provides a detailed report within a relatively short time of the area for the developer/contractor. Developers are able to make quicker assessments concerning the implications of the antiquities found at a project site.

Licensing Excavation and Survey

According to the antiquities law in Israel all archaeological excavations and surveys require a license. It is issued by the director of the IAA and regulates the utilization of archaeological resources, monitoring of finds and ensures the scientific rights of research.

Since 1959, excavation licenses for sites in the State of Israel have been given to professional archaeologists coming to dig there from around the world. Currently the excavation license specifies a rectangle for the area to be excavated (all geographic data is AN represented). The license also guarantees scientific rights for the research. The area must be defined as accurately as possible and lay within the declared area of the site.

In the past, because of the limitations of the database, the geographical data was not verified properly. It actually was very difficult to make the required comparisons between the site and the boundaries of the excavation license and this was often the source of errors.

Today, GIS is used to assist the license manager in defining correctly the boundaries of a requested excavation/survey versus the defined boundaries of the archaeological site. All mismatches are now reported so the process is much more reliable. The use of modern GIS techniques is especially important when dealing with a multi-part boundary or a curved shape, which is very difficult to describe by alphanumeric data only.

Surveys

All modern archaeological research begins with field survey. These are regularly carried out by systematically exploring wider regions or by visiting specific sites where archaeologists examine and document surface remains.

Over the years the IAA surveyors have collected varied data on archaeological sites, from basic coordinates to detailed drawings and photographs. All this data was stored in paper documents and old fashioned archives. As the volume of the data grew it became increasingly difficult to manage. In addition, it was not possible to perform even the most basic statistical analyses on the data. It was also not possible to integrate GPS data properly into the survey work. Today, IAA uses GIS as a geographic database and the surveyors can:

View and produce maps of the archaeological remains (recorded as DGPS data) along with its AN data and photos.
Run statistical analyses on the data and reconstruct ancient landscapes.
Enables the surveyors to work uniformly with the same data dictionary and symbology of archaeological sites.

Archaeological excavations

Field excavations are conducted for scientific research, to salvage as much information as possible from an archaeological site destined for destruction due to land development and also for tourism.

Up till recently IAA archaeologists manually processed excavation data, daily basket logs, field drawings and so on. The computerized excavation databases where not standardized and had many problems. Consequently, IAA was lacking

Efficient quality control of the field data collected.
Database standard for the organization
Possibility for integration stored data between different excavations
Integration of alphanumeric and geographic data

IAA is now beginning to apply GIS technology in order to build a computer-based field excavation system that supports the entire process and enables the archaeologist to examine alphanumeric and geographic data together.

The new database system is called ADAMA (Archaeological Database Management Application). It consists of an MS-Access based alphanumeric database compatible with the central Oracle database and an ArcView based geographic database.

The system represents:

GIS: daily excavation plans and locus boundaries registered on the real world Israel coordinate system and created using both a distomat and a DGPS receiver.
Database: daily records of loci and baskets as well as the findings.

Since the geographic data is geo-coded it enables the archaeologist to:

Map artifact distribution (basket to loci resolution) (fig.4).
Map archaeological periods on the basis of loci and wall.
Geographically accurate and up-to-date computerized daily logs, site plans and sections (fig.5,fig.6).
Various additional GIS oriented views and reports from the database .

Summary

The implementation of GIS in the IAA has given the organization a set of revolutionary data management and presentation tools. They provide accurate and fast methods for collecting, integrating and presenting archaeological data.

The GIS applications that have been so far developed for the IAA support five functions: the declaration of sites, supervision of work, surveys of regions and locations and improved recording of excavation work at archaeological sites.

The IAA still has a long way to go in implementing the new technology and to support all aspects of the work within the organization. We are convinced that in the not too distant future the GIS tools will have a major impact on many aspects of the scientific archaeological research.