## 5 Conclusions  
This paper for the first time assesses the potential of satellite SAR X-band COSMO-SkyMed data in the detection of archaeological marks (crop, soil and shadow) in different environmental conditions. To  
Figure 19: Metapontum: the temple area and a road (indicated by red arrows) in the ancient Greek town. Google Earth scenes were acquired on: (**a**) 22 September 2004; (**b**) 8 June 2006; (**c**) 11 August 2006; (**d**) 8 May 2013.  
Figure 20: Metapontum. (**a**) The temple area and road in the ancient Greek town observed from COSMO-SkyMed Spotlight image; (**b**) enhancement of (**a**) result of the sum of squares of the Lee algorithm product.  
this aim, significant case studies were selected in desert (Sabratha, Libya) and vegetated areas (Metapontum, Italy and Luoyang, China).  
Moreover, it assesses for the first time the potential of SAR X-band data using two different feature-enhancement procedures: (i) multi-temporal analysis and; (ii) single-date analysis.  
A multi-temporal data set, based on 40 scenes of Stripmap HIMAGE data, was used to investigate the Eastern-Han to Northern-Wei Dynasty Luoyang city site (China). The archaeological site, dating back to 100-500 AD, is located in the east-original section of the Silk Road, in the Henan Province (China). Crop, soil and damp marks are only visible from optimal-selected single date due to seasonal nature of these archaeological features. Whereas shadow marks are visible from both single and multitemporal data analysis.  
Single data analyses were applied to Sabratha (Libya) and Metapontum (Italy). These case studies were selected because they have diverse superficial conditions (desert and Mediterranean area) and archaeological marks (crop, soil and shadow). In particular, Sabratha is characterized by shadow marks linked to the presence of microrelief and shallow walls; in Metaponto most of the archaeological features is given by vegetation and moisture changes.  
Among the key outcomes, our analysis highlights that the methodological approach adopted demonstrated that both multi-temporal and single-date analysis are suitable for the enhancement of archaeological and palaeoenvironmental features.  
The main findings of the archaeological investigation performed can be summarized as follows:  
* The use of multi-temporal COSMO-SkyMed Stripmap, by stacking-averaging has been beneficial for shadow mark enhancement. On the other hand, visual inspection enabled us to identify the best scenes for the reconnaissance of the \"seasonal\" archaeological feature (crop, soil, and damp marks). This was probably due to a good match between soil properties and the acquisition parameters of the image itself.
* Single-date analysis was a feasible way to provide an effective and cost-sustainable use of satellite SAR X-band data to detect archaeological features, from the shadow marks (Sabratha) to marks sensitive to vegetation (Luoyang and Metaponto) and moisture variations (Metaponto).  
One of the strengths of this research is the demonstration, that even a single COSMO-SkyMed Spotlight acquisition is a feasible and effective approach for archaeological prospection. The reduction of data processing complexity as well as the cost for data will contribute to increasing the use of satellite SAR X-band in archaeological investigations.  
The way forward of such type of research is to continue investigations in order to study how the image acquisition parameters (frequency, polarization and angles of incidence) affect and/or enhance the visibility of the diverse archaeological mark typologies (shadow/crop/soil/damp marks).