Globally, more people live in urban areas than in rural areas, with 54 per cent of the world’s people residing in urban areas in 2014. In 1950, 30 per cent of the world’s population was urban, and by 2050, 66 per cent of the world’s population is projected to be urban. In particular, Asia and Africa will surpass the value of 50% of the urban population in 2020 and 2035, respectively [1
]. This current situation and the expected future scenarios impose the need for a ‘sustainable development’ as a key factor in the programs of many governments, businesses, educational institutions and non-government organizations around the world. Actually, ‘sustainable development’ is a dynamically evolving concept without a unique definition. Historically, it has expressed the need to integrate ecological and economic principles into personal and public decision-making. The Bruntland report, the Rio Conference and the Istanbul Habitat II Conference definitely underlined the importance of social and economic dimension of environmental sustainability [2
]. Subsequently, a new concept of sustainability has been put forward, which underlines the importance of including environmental criteria in territorial development choices, rather than supporting specific protection policies, indicating boundary thresholds for resource use and consumption. According to this idea, all decisions about new government interventions are taken with the respect to environment carrying capacity [4
Although urban growth is perceived as necessary for a sustainable economy, uncontrolled or sprawling urban growth can cause various problems such as loss of open space, environmental pollution, traffic congestion, infrastructure pressure, landscape alteration, threats and/or destruction of archaeological sites and cultural landscape [9
]. It is important to highlight that today cultural heritage is increasingly threatened with destruction not only by the traditional causes of decay, but also by changing social and economic conditions which aggravate the situation with even more formidable phenomena of damage or destruction (from the general conference of the UNESCO meeting in Paris from 17 October to 21 November 1972, at its 17th session, available online) [10
]. To face these drawbacks, a continuous monitoring of the urban growth in terms of type and extent of changes over time is essential for supporting planners and decision makers. The analysis of city size distribution deals with different disciplines such as geography, economy, demography, ecology, archaeology, physics, statistics because the evolution of a city is a dynamic process involving a number of different factors. For each of these diverse factors, the main issue of great importance in understanding, modeling and managing urban growth includes estimation of current and future spatial and temporal dynamics as well as the effects of urbanization and man-induced changes [11
]. Therefore, for planning and monitoring urban expansion processes in a ‘sustainable development’ approach, a critical point is the availability of information on past and current conditions to estimate potential future scenarios. In this context, satellite data (also available free of charge) can provide both (i) a historical time-series data set; and (ii) timely updated information related to the current urban spatial structure and city edges [12
]. The use of satellite imagery along with spatial analysis techniques (see, for example, [13
]) can be fruitfully used for improving knowledge and documentation of cultural heritage sites (see, for example, [14
]) as well as for monitoring and planning purpose recording ongoing trends of urban growth [19
] and estimating natural and anthropogenic risks [22
] at a detailed level. The analyses of the historical data set of satellite images provide detailed information on the evolution of the size and distribution of urban areas and agricultural lands that constitute key information that is useful for supporting both the management of future city growth and the implementation of strategies to mitigate the negative impacts on environment, ecosystems, cultural sites and archaeological landscape.
A multidisciplinary approach based on the cooperation of diverse scientific communities, as archaeologists, earth and remote sensing experts, and other scientists and engineers, can successfully address the challenge of supporting both the needs related to social and economic development and the preservation of cultural heritage [23
]. As an example, in redeveloping urban areas there is a need to provide adequate foundations for new buildings and structures, while at the same time preserving, as far as possible, sub-surface archaeological remains.
Conservation and protection policy addressed to preserve cultural heritage and landscape is a pressing issue today, especially for sites and areas that significantly represent the cultural identity of a territory, population, country, civilization. Moreover, it is important to highlight that archaeological sites, cultural properties and landscape are non-renewable resources and they hold specific cultural values for mankind that need to be preserved for the present and future generations. These assets are also important economic resources and, in view of increasing public interest, an organized approach to decision making would assure the conservation and preservation of the various values of the archaeological sites and cultural landscape, including their educational and economic potential. In this context, remote sensing technologies [26
] can offer both useful data to timely update information and documentation and reliable tools for systematic monitoring of cultural properties, for the monitoring of urban sprawl [28
], to the estimation of stabilities of ancient buildings [29
] and the study of archaeological landscape and buried structure [30
Today, the tremendous availability of advanced remote sensing data has opened a new prospective that was unthinkable several years ago. In particular, remote sensing can provide useful data not only for probing the subsurface to unveil unknown sites and artefacts, but also for the management, valorization and preservation, for detecting changes as well as for assessing degradation and emerging threats. A sustainable planning and design can fruitfully find the technical solutions and make it possible to find space for the new preserving the ancient past heritage. Alessandria (Egypt) and Shush, (Iran) were selected as study areas for our investigations.
The analysis of Corona imagery in Kom el Shoqafa revealed that the urban area increased by about 2315 km2
from 1964 to 1984 about 6777 km2
from 1984 to 1998, and finally about 3634 km2
from 1998 to 2016. For the urban areas in Shush there was an increase of about 1433 km2
from 1964 to 1984, about 945 km2
from 1984 to 1998 and about 1012 km2
from 1998 to 2016. On the other hand, we can see that the agricultural lands in Kom el Shoqafa decreased by about 6178 km2
from 1964 to 1984, but decreased by about 108 km2
from 1984 to 1998, and the agriculture lands increased by about 2128 km2
from 1998 to 2016. For Shush, the agricultural lands decreased by about 4528 km2
from 1964 to 1984, and decreased again by about 141 km2
from 1984 to 1998. Then, the agriculture land decreased again by about 23 km2
from 1998 to 2016 (Table 3
). We used a contingency table to compare land use maps between four time periods for each region to quantify the amount of land use change for each land use class [53
]. It means that the urban areas sprawling in Shush and Kom el Shoqafa (Figure 15
and Figure 16
) through the population increased have clearly effected the agricultural land’s change into urban use (Figure 17
and Figure 18
). For the urban area, the evaluation of the change detection presented generally increasing chronology in both of the study areas, but for the agriculture lands we can see that the changes were sometimes decreasing and sometimes increasing.
Classification algorithms help to understand the existing pattern in data and can be used to predict the land use class using suitable data mining techniques [54
]. Corona and Landsat TM and L8 imagery were used to detect the changes in the urban and agriculture lands at Kom el Shoqafa (Egypt) and Shush (Iran). Using integration between Envi and ArcGIS software, the changes were detected chronologically from 1964 to 2016. Final change detection analysis quantified and described the differences between the images of the same scene at different times. The classified images of the four dates can be used to calculate the area of different land covers and observe the changes that are taking place in the span of data.
Today, advanced information and communication technologies represent the most innovative aspects of many scientific disciplines, and this is especially true of the Cultural Heritage sector, where there is a growing demand from the public, at the local community level, for education and the management of cultural heritage with a view to increasing tourism [56
]. Remote sensing is one of the main foundations of archaeological data, underpinning knowledge and understanding the historic environment. The potential of remote sensing can be achieved by placing a particular focus on archaeological heritage management. Well-established approaches and techniques have been used alongside new technologies and data sources, with discussion covering relative merits and applicability, and the need for integrated approaches to understanding and managing the landscape [57
]. Urban development, related population growth, and environmental changes [58
] can all be detected via remote sensing analysis, and the importance of locating archaeological sites to preserve and protect them has been stressed [59
]. A range of generic software tools to aid the documentation, inspection and maintenance management of cultural buildings has been developed. Expert systems, containing, for example, the knowledge for diagnosis of damage/decay of (pointing) mortars have been realized [60
In this paper, in order to recover the lost information and set up a systematic monitoring of ongoing changes close to archaeological areas of Kom el Shoqafa (Egypt) and Shush (Iran), we propose the use of historical archives along with recent satellite acquisitions. The data set is obviously made up of heterogeneous remote sensing images which can enable the recovery and recording of important formation on the past land use around two important archaeological areas Kom el Shoqafa (Egypt) and Shush (Iran). Results have been developed that take advantage of GIS and RS based on the utilization of a variety of environmental factors. Our approach addresses the challenges in using heterogeneous data from multiple data sources for change detection analysis to improve knowledge and monitoring of landscape over time with a specific focus on urban sprawl and land use change around archaeological areas. The change detection we performed is based on the use of a heterogeneous optical imagery data set, made up of satellite declassified Corona imagery and the more recent Landsat TM data. There are many techniques nowadays available to capture and record differences in two or more images acquired, that can be summarized as follows: (i) if the images come from the same sensors, the change detection is generally based on image differencing, ratios or correlation; (ii) if the data set is made up of heterogeneous images the post classification comparison is generally adopted. Moreover, it is really important to highlight that data preprocessing is an important procedure for change detection analysis. In particular, the comparison between satellite images taken form the same scene at different acquisition dates needs the images under analysis to be co-registered. In particular, the analysis of Corona and Landsat TM, ETM+, L8 imagery in Kom el Shoqafa revealed that urban areas increased by about 18% from 1964 to 1984, about 53% from 1984 to 1998 and finally about 29% from 1998 to 2016. Similarly, the urban areas in Shush increased by about 42% from 1964 to 1984, about 28% from 1984 to 1998 and are still today increasing around 30% from 1998 to 2016. On the other hand we can see that the agricultural lands in Kom el Shoqafa were decreased by about 72% from 1964 to 1984, and again decreased by about 1% from 1984 to 1998, but the agriculture lands increased by about 25% from 1998 to 2016. For Shush the agricultural lands decreased by about 76% from 1964 to 1984, and decreased again by about 22% from 1984 to 1998. Then, the agriculture land decreased again by about 4% from 1998 to 2016.
These changes are to the young farmers’ decision to try to invest in relatively low-priced, yet quality areas for agricultural purposes. In addition, some positive changes occurred in some land covers as in the case of natural grassland areas, which represent a middle phase of development between agricultural lands and urban areas, as farmers turn them into areas for building their houses (or to sell it as building area with much higher price). Some farmers, however, seem to neglect their agriculture land on purpose in Kom el Shoqafa [61
]. All of these (bio) physical changes within the setting of the region’s ecosystems of Shush reflected the dynamics of human impacts on the study area.
Reconciling the demands of waste disposal and urban subsurface engineering as well as those of water supply, some degree of degradation will be unavoidable. Examining the effects each have on the subsurface can help develop the integrated approach so necessary to avoid serious long-term degradation [62
]. Expert GIS tools, including statistical and other numerical techniques, can transform inputs from GIS modeling into derivative layers—and such layers can be exported into computer models. This results in the much more efficient use of the professional’s time, with more time spent on critical decisions about model boundaries and parameters and less time transcribing information. Computer models will need refinement in order to accurately represent pumping cycles (transient conditions) and to create detailed management zones within regional models. Predictions of cause and effect can be made and management scenarios explored. Fully developed groundwater models can inform management decisions. Publically available GIS mapping tools allow anyone with internet access to explore spatial relationships between existing data layers [63
]. In addition, it is also evident that there is a need for a more complete protection of geosites from potential human-induced threats (e.g., urbanization, human-induced coastal erosion, waste disposal, mineral/aggregate extraction) [64
In summary, the output from our investigations clearly highlighted that satellite data can provide very useful tools for (i) capturing land use changes along with impact induced by human activities at a site level; (ii) monitoring environmental problems with a particular attention addressed to the urbanization and changes in land use/land cover with particular reference to areas in close proximity to archaeological areas and cultural landscape. It is very important for researchers to understand the dramatic changes that have occurred due to human activity during the last decades. The analyses of the historical data set of satellite images provide detailed information on the evolution of the size and distribution of urban areas and agricultural lands that is key information useful for supporting both the management of future city growth and the implementation of strategies to mitigate the negative impacts on environment, ecosystems, cultural sites and archaeological landscape. As suggested by UNESCO, satellite images provide a means to improve the information flow and communication among site managers and conservation authorities: an image is worth a thousand words.
The results from our investigations conducted using data acquired in 1964, 1984, 1998 and 2016 clearly showed that the spatial dimension of the urban areas significantly increased for both the study areas Kom el Shoqafa (Egypt) and Shush (Iran). Analyses were based on the use of the Corona and Landsat TM, ETM+, L8 imagery, processed using different steps. (i) Geometric correction, unsupervised classification, supervised classification and post classification analyses to extract and quantify the most significant changes. These case studies present an experience in terms of planning and design that makes it possible to think of a sustainable use of heritage resources and their relationship with tourist space design. Moreover, this proposal sets a precedent and may be applicable to other projects, with the necessary adaptations depending on the particular contextual circumstances. The aims of this study were focused on detecting the result of urban sprawl, which appeared in the both study areas. This urban expansion affected the archaeological area, so we created some solutions which were supported by the integration between space images and GIS techniques. We can conclude that: (i) the current availability of long term satellite time series provide an excellent tool to observe and monitor changes from a global down to a local scale; (ii) additional improvement are expected to be obtained in the future using active and passive satellite data from Sentinel 1 and 2 provided free of charge by the European Space Agency (ESA).