## 3 Conclusions and Future Perspectives  
In this paper, the feasibility of the Sentinel-1 satellite to provide InSAR-derived ground deformation map for Great Britain has been analysed in relation to the availability of archived stacks of imagery suitable for interferometric applications, terrain visibility for the two radar acquisition geometries, the density of good radar reflectors for the various land cover types, and the kinematic and geometrical constraints of the investigable phenomena. We showed that topography exerts limited control on the visibility of the British landmass, with only \(\sim\)1.0% of the total territory potentially affected by radar shadow and layover to the Sentinel-1 IW modes in each acquisition mode. Calibration of the CLC2012 using seven external ISBAS datasets allowed the characterisation of the land cover classes in terms of the average of potential pixel density that ISBAS could provide for each category. Despite the predominance of non-urban land cover across the landmass, the Sentinel-1 shorter repeat-cycles combined with an improved processing technique like ISBAS addresses the need for more dense networks of monitoring targets across rural and partly-vegetated regions with an average density of 90 ISBAS/km\({}^{2}\) and a potentiality of \(\sim\)22,000,000 pixels for each acquisition mode covering Great Britain. Furthermore, all of the Great Britain landmass, as of 2016, has enough IW acquisitions (\(\geq\)30 on average) to guarantee satisfactory results in terms of standard deviation of the LOS velocity as shown in the Doncaster test site.  
The implementation of the ground motion study of the whole of Great Britain with interferometric measurements aim to:  
* Provide information at regional and national scales to identify ground displacements that occur over hundreds or thousands of square kilometres and characterise areas prone to risk because they are affected by critical geohazards. With such information decision-makers (e.g., UK Oil and Gas Authority, Coal Authority, Environmental Agency, or Health and Safety Executive) can analyse and evaluate different scenarios and plan specific actions based on homogeneous and reliable measurements. Furthermore, InSAR data can be updated regularly as more Sentinel-1 images are acquired, and can provide new ways to design early warning systems covering entire nations, where satellite information can highlight areas where in situ sensors and continuous monitoring tools should be installed or field checks should be optimized.
* Realize an important database to encourage the sharing of methodologies, data, and results. In this regard the manual data analysis and interpretation of \(\sim\)22 M ISBAS points makes the process cumbersome, operator-dependent, and time-consuming, while semi-automated methodologies can be particularly advantageous for analysing and classifying remote sensing data at the regional scale.  
Figure 11: The inverse relationship between the number of interferograms and the LOS standard deviation for the Doncaster area.  
**Acknowledgments:** [PERSON], [PERSON], and [PERSON] published with the permission of the Executive Director of BGS.  
**Author Contributions:** [PERSON] and [PERSON] conceived and designed the experiments; [PERSON] and [PERSON] performed the experiments; all the authors analyzed the data; [PERSON], [PERSON] and [PERSON] wrote the paper.  
**Conflicts of Interest:** The authors declare no conflict of interest.