APLADYN project: anthropogenic and landscape dynamics in large fluvial systems

On 16 June 2014 a number of our project members presented the results of their remote sensing research at the 34th EARSeL Symposium in Warsaw, Poland: European Remote Sensing - New Opportunities for Science and Practice. This research was carried out within the APLADYN project: a Belgian Science Policy project on anthropogenic and landscape dynamics in large fluvial systems. The abstracts of these talks can be found here.

From space to place: using photogrammetry and its derived products for Egyptian archaeology and geomorphology in the area of Dayr al-Barsha, Middle Egypt

Marijn Hendrickx, Veronique De Laet, Gertrud Van Loon, Bart Vanthuyne, Harco Willems, Gert Verstraeten, Rudi Goossens

Abstract:

Documenting and mapping cultural heritage is an important aspect nowadays in geo-archaeological research. The rapidly changing surroundings of Dayr al-Barsha where not only physical but also anthropogenic dynamics strongly influence the environment are no exception. Although archaeologist and geomorphologist work nowadays with remote sensing data, it is mainly done in two dimensions. The third dimension can complement this data because it introduces the height component which is quite important in mapping and analyzing archeological and physical environments. This height component can be introduced using photogrammetry and using its derived products like digital surface models (DSMs) and orthoimages The elevation data is generated out of stereoscopic images from not only satellites like Corona, Worldview and GeoEye but also terrestrial photography and ground control points taken in the field. First of all DSMs and orthoimages have been computed using satellite images from 1970,2009 and 2012. The most recent ones are further used as a base map to plot archaeological sites. Contour lines acquired from the generated DSMs are a perfect tool to better understand the (natural) environment of these features. To analyze anthropogenic and physical landscape dynamics, a pixel-wise subtraction is used on the DSMs from the different periods. This results in quantifying village changes, river bed movement and estimated dune volumes. Photo modeling out of terrestrial images is a second approach in this work. To accurately document and reconstruct different archaeological objects, they were photographed, measured and processed, using photo modelling software. A main example in this case was a weaver loom dug out in a quarry. Using this photo modelling approach and literature we were able to reconstruct the loom. The elaborated work illustrates that photogrammetric techniques hold great potential for geo-archaeological research from different image sources and at different (time) scales. This abstract fits within the APLADYN project: a Belgian Science Policy project on anthropogenic and landscape dynamics in large fluvial systems.

 

Analysis of the aeolian-fluvial-human interactions in the Nile valley (central Egypt) by combining field-based geomorphology with remote sensing

Gert Verstraeten, Ihab Mohamed, Harco Willems, Veronique De Laet, Jose Manuel Delgado Blasco

Abstract:

Interactions between aeolian processes and fluvial processes are important in shaping and transforming the landscape of large river systems in arid environments. This is in particular the case for the River Nile in Egypt where dune fields are entering the floodplain thereby not only destroying fertile agricultural land but also impacting the preservation of cultural heritage from former time periods. An integrated study combining traditional geomorphic field-based approaches, terrestrial geophysics as well as multi-temporal analysis of remote sensing imagery provides more information on the temporal evolution of the interaction area between the South-Rayan Dune Field (SRDF) and the Nile valley in central Egypt for the last 5000 years. Results show that the interaction area has been very dynamic whereby the invasion of dunes has impacted agricultural activities from the Old Kingdom period. Several cultivation layers, the oldest dating from the onset of the Old Kingdom, could be detected illustrating the presence of humans in a fluvial landscape that becomes influenced by aeolian processes from the mid-Holocene onwards, which is related to the general drying trend in Northern Africa. The ongoing migration of dunes preserved this Pharaonic agricultural landscape and possibly also important settlements from this time period. Through time the Nile floods were more and more blocked by invading dunes, although the sand flux into the Nile valley was insufficient to block the Nile itself. It is, however, suggested that invading sand dunes shifted the Bahr-Youssef channel further east. Sand flux estimates were provided by measuring contemporary dune migration rates through multi-temporal analysis of optical and radar imagery. At present, the major process shaping the interaction area is of anthropogenic origin. Field observations and satellite images from 1963, 1984 and 2003 showed that dunes are being removed at high rates by quarrying activities, leveling, irrigation and the establishment of agriculture. As such, these sediment archives providing valuable information on the Holocene fluvial-aeolian-human interactions, and thus can be considered are being a specific form of both cultural and natural heritage, are being obliterated at a very high rate. This abstracts fits within the APLADYN project: a Belgian Science Policy project on anthropogenic and landscape dynamics in large fluvial systems.

 

Integrated Remote Sensing Investigations of Ancient Quarries and Road Systems in the Greater Dayr AI-Barsha Region, Middle Egypt: a Study of Logistics

Veronique De Laet, Gertrud Van Loon, Athena Van der Perre, Harco Willems, Gert Verstraeten

Abstract:

Although the study of stone quarries is gaining increasing importance in Egyptian archaeology, quarry logistics, particularly as concerns transport facilities, has hitherto hardly been investigated. In the case of the quarry roads in the greater Dayr al-Barsha region (Middle Egypt), distinguishing between roads related to quarry exploitation from those resulting from other periods of use (in this case mainly related to funerary cult and Late Antique-Early Islamic monastic communities) poses another methodological problem. In this paper the use of very high spatial resolution satellite (VHSRS) technology is combined with archaeological methods to investigate the interplay between limestone quarries and roads in the study region. Remote sensing affords significant advantages over traditional survey techniques by visualizing the spatial context, whereas the spectral information content of the imagery adds information on road characteristics. Results indicate that spectral content is of less importance for road detection in desert-like conditions than the spatial resolution of the imagery. Filtering techniques have an additional value, but in general enhancement techniques such as histogram equalization are most important for mapping road networks in the greater Dayr al-Barsha region. Based on spectral and morphological characteristics, six road types could be identified, a seventh being located using traditional techniques. Ground verification in conjunction with archaeological evidence clarified the spatial context and functions of the routes in the pharaonic and later periods, serving cemetery, quarry and settlement logistics. Apart from one Middle Kingdom processional road, most roads have their origin in New Kingdom quarry activities. The road pattern we discovered provides important indications on how the stone transport was organised in a practical way. Many quarries in Dayr Abu Hinnis were not connected to harbours along the Nile, but to a long desert road that facilitated  talatat transport to an area in northern Amarna. When the abandoned quarry complexes were turned into settlements in the Late Antique-Early Islamic Period, the resident communities selected parts of the existing road system for inter-site transport and transport from and to and the Nile Valley. New paths were only rarely developed. These observations demonstrate that remote sensing techniques hold great potential for surveying road patterns over large distance in desert-like conditions. This abstract fits within the APLADYN project: a Belgian Science Policy project on anthropogenic and landscape dynamics in large fluvial systems.

 

  
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