The EAIS mapping system is designed to handle detailed data on the location, area, and legal statuses of all historical sites in Egypt in a clear, simplified form. It allows for storing, integrating and analyzing data at different scales and backgrounds, and makes it possible to include several levels of information, such as site boundaries, buffer zones, and urban and agricultural areas. At the same time, the GIS assists in performing several levels of threat analysis for historical sites.
The mapping system deals with two main data categories: spatial location and background data.
Spatial Location Data
Spatial location data is collected from several sources. Official data on site locations is obtained from the SCA, while other governmental institutions, international organizations, archaeological missions, and books provide supporting data. The official data is the basis of the system; the other sources are used to verify, update, and expand upon EAIS’s information. The Egyptian Survey Authority (ESA), the National Authority for Remote Sensing and Space Sciences (NARSS), and the Ministry of Agriculture are EAIS’s main sources for background data such as satellite images and cadastral maps.
Data is input into the system in either raster or vector format. The system also uses other data sources, such as GPS points, to add to the scope of information available.
General Site Locations
The general location of a registered SCA site is represented by a centroid. Point locations are determined from the pool of available sources, such as official maps, publications, and archaeological missions, or through the calculation of centroid from the verified site boundaries. centroids are calculated according to UNESCO guidelines. Each point is connected to basic site information: its name, X-Y coordinates, and the types of archaeological material represented. The accuracies of centroid vary according to its original source, but expressing sites in this manner gives the viewer a general idea of site location and distribution—a valuable perspective for the SCA, land use planners, and decision-makers.
Specific Site Locations
Information on site boundaries comes initially from Amlaak, the SCA's surveying and property department. The scale of these original maps is usually 1:2,500 in the urban and agricultural areas but it varies to other un-detailed scales outside these areas i.e. in deserts.
Site boundaries are shown as vector polygons, giving users of the system a precise view of the location and dimensions of the site. Each polygon is attached to detailed site information, such as the site’s name in Arabic and English, and its area—both in square meters and in feddan, qirat, and sahm, traditional units of land measurements in Egypt. A unique ID code links each of these sites with the supplementary information in the database. However, a few Islamic sites are drawn as points as the property itself can be very small (a minaret or even an individual object such as an icon) and there is a lack of accurate maps, making the use of points preferable.
These boundaries are the heart of the system. These are the lines land use planners rely on when making their decisions and these are the lines the SCA relies on when determining intrusions upon the site.
The mapping system can also handle supplementary information, such as detailed site plans. This comprehensive treatment is primarily done on sites for which detailed information is available—usually from archaeological missions—or sites for which detailed information needs to be produced. This allows EAIS to take full advantage of the most thorough archaeological research as well as play an important role in preservation and emergency excavation measures.
Background Data
Background maps form an important component of the system. Primarily obtained from governmental sources, these maps are used to provide a context for GIS analysis and are of several types: from raster topographical maps and satellite images, to vector maps, land use categories, urban areas and administrative boundaries. Background maps present information on changes in land use around cultural heritage sites and can be combined to assist in different kinds of analysis. Site boundaries, for example, are superimposed on the latest cadastral maps to provide information for site protection and land use planning.
Of the many backgrounds available in the system, five main backgrounds were selected to be consistently used when available. When seen with the site borders, the selected backgrounds show information such as urban expansion, plot numbers, and relationship to topographical features. Among other uses, such information can be applied to detect changes to sites over time and the relationship of site boundaries to the rest of the environment.
The following is a brief explanation of each of the five aforementioned backgrounds and their uses:
Amlaak Maps
Amlaak maps are ESA maps that the Amlaak Department uses to record the borders of the archaeological sites. They are the official source for SCA’s site location and boundaries. Their scale varies: Amlaak usually uses 1:2,500 maps for NileValley and the Delta, and 1:25,000 or 1:50,000 maps for remote areas. The borders are drawn by hand and colors are used to mark legal statuses. Sometimes the maps may contain handwritten notes about the area and ceded sections.
Ministry of Agriculture Maps
These are updated ESA 1:2,500 cadastral maps on which urban expansion until 1985 is indicated by the Ministry of Agriculture using aerial photographs taken in 1984. These maps are used extensively by local authorities and land use planners.
Updated ESA 1:2,500 Cadastral Maps
These maps are updates of ESA cadastral maps and show detailed land ownership information, including parcels and plots numbers. They are useful verifying site borders against legal decrees. Production of these cadastral maps began in the 1930s and they have undergone continuous revision and expansion since then. The series is kilometric, using the Egyptian Transverse Mercator (ETM) projection system, so distances are related in terms of meters and kilometers, rather than degrees and seconds.
ESA 1:50,000 Topographical Maps
These maps show urban agglomerations along with topographical features, such as roads, railways, and irrigation canals. Superimposing site boundaries on these maps shows the relationships between archaeological sites and these features.
Topographical Vector Layers
Vector layers are simple to work with and offer a great potential for spatial analysis. These layers are digitized from 1:50,000 maps produced in the 1990s. The maps show the boundaries of urban areas as updated using satellite images from 1999, thus showing the development of urban expansion from 1993 to 1999.
