Motivation

At the center of the Heliopolis project is the temple district of the ancient Egyptian sun god in the Matariya district of Cairo. As the mythical birthplace of the Egyptian gods, Heliopolis assumed the role of an important religious center from about 2400 BC (Old Kingdom) to the 4th century BC (Ptolemaic period). This special status is reflected in the dimensions of the sacred site. Walls up to 17 meters thick and 10 meters high once enclosed the area, which covers one square kilometer.

Due to its location in the center of the growing metropolis of Cairo with its many millions of residents, the area is threatened by illegal land grabbing. Increasing construction on the borders of the 300 x 400-meter open space have also led to a continuous rise in the groundwater level for years.

From 2016 to 2020, the i3mainz was responsible for, among other things, the development and implementation of a research data management system in the project as part of the three-year project funding. The results of the archaeological work were compiled in a GIS, which serves as a reference system for archaeological documentation.

Activities

The i3mainz supported the excavation team in documenting the finds as completely as possible in the shortest possible time to reduce the traditional description, measurement and drawing tasks in the emergency excavation. The concept developed for this purpose combines established photogrammetric methods with defined processes for archiving the results obtained.

Another focus was on the sighting, sorting and processing of historical maps of the temple area and its surroundings. Suitable historical maps were then georeferenced to create GeoBase data for the project and provide a reliable, quality-controlled basis for future work.

In the Heliopolis project, the involvement of the i3mainz did not end at the use of specialized modern measurement methods, the institute also worked on the development of a strategy for making these methods available for further scientific evaluation in a long-term and comprehensible manner. The concept covers the entire chain from the acquisition of reliable 3D information to the preparation of the data for proper publication and long-term archiving.

In joint workshops with the project’s partner in Leipzig, metadata models, tools and procedures customized to the project were developed, along with guidelines adapted to the project. To ensure the quality of the newly created data and simultaneously reduce the documentation effort in the field, adjustments had to be made to the methods used to collect data in the field in some places. Structure from motion (SfM) is now widely used by the section leaders for documenting planum and findings. This methodological change was greatly appreciated, primarily because of the time saved in the field and the high density of data.

In March 2017, the excavation team at Matariya found the head and torso of a colossal statue of an ancient Egyptian ruler with an inscription naming the pharaoh Psamtik I (664-610 BC). Several thousand additional smaller fragments have since also been recovered.

Results

The i3mainz adapted modularized documentation and archiving processes to existing workflows, optimized established digital methods, and introduced structure from motion as a regular documentation tool in the daily excavation process.

These measures subsequently made many of the archaeological interventions possible in the first place. Direct knowledge transfer was ensured by regular workshops in Leipzig and Mainz throughout the duration of the project.

The following results were achieved in the course of the project-related work on data management and the digital reconstruction of the temple and its topography:

• Guide for the quality-assured capture of finds and observations with structure from motion.
• Guide for the digital xml-based documentation of results of geomorphological drillings with Groundhog Desktop software from the British Geological Survey (BGS).
• A schema for systematic file- and directory-based storage of Heliopolis research data.
• Metadata schemas for digital photographs and georeferenced maps.
• Generation of archaeological geospatial data for Lower Egypt, including digital terrain models showing the reconstruction of the Nile Delta in the 2nd and 1st millennia BC.
• Quality-checked georeferencing of all available 19th and 20th century topographic maps of the area.
• Consolidated compilation of all geodetic survey data from work at Heliopolis from 2006 to 2018.

As part of a neutral-cost extension, the project was completed in the spring of 2020 and a new application was submitted to the German Research Foundation (DFG) for the exploration of specific questions regarding the abandonment of the temple and its afterlife in spiritual history, which was approved in 2021.