## 4 Results
### Vegetation Indices  
As mentioned earlier, the calibrated optical and radar bands were retrieved from the Sentinel Hub platform. Based on the equations provided before Equations (1) and (2) the NDVI and the RVI  
Figure 3: Sentinel-1 and Sentinel-2 datasets and ready products downloaded from the EO Browser of the Sentinel Hub Service used in this study. (**a**) orthorectified Sentinel-1, VH polarization, gamma 0, (**b**) orthorectified Sentinel-1, VV polarisation, gamma 0, (**c**) Sentinel-1 Synthetic Aperture Radar (SAR) urban visualization product, (**d**) Sentinel-1 Radar Vegetation Index, (**e**) Sentinel-2, Bottom-of-Atmosphere (BOA) Band 5, (**f**) Sentinel-2, Bottom-of-Atmosphere (BOA) Band 8, (**g**) Sentinel-2, Normalized Difference Vegetation Index (NDVI), (**h**) Sentinel-2, Scene Classification product, and (**i**) the OpenStreetMap vector data of the area. The scale for all sub-figures is shown in the right bottom part of the Figure 3.  
were estimated (also see Figure 3d-g). The range of these indices is between \(-1\) to \(+1\) for the NDVI while for the RVI the range value is between 0 to \(+1\). With the increase of vegetation cover, the value of both indices increased to \(+1\). At the same time, non-vegetated areas are close to 0 (and negative for the NDVI in water bodies). Since the acquisition period for the Sentinel-1 and the Sentinel-2 images only had a one day difference, it was hypothesized that both indices were obtained at the same phenological status of vegetation. The results from the application of the vegetation indices over the area of interest are depicted in Figure 4. Figure 4a,d,g show the Sentinel-2 true colour composite over the area of interest, the archaeological site of \"Nea Paphos\" and the historic Centre of the Paphos town, respectively. Likewise, Figure 4b,e,h display the results of the RVI, while Figure 4c,f-i show the results from the NDVI. Vegetated areas as estimated from the RVI (Figure 4b,h) are shown with a green colour while non-vegetated areas are visualized with a black colour. Vegetated areas in the NDVI (Figure 4c,f-i) are highlighted with a dark-green colour and non-vegetated areas with a light-yellow colour. From Figure 4, it is evident that optical products are more easily visually interpreted compared to the radar products, however, this could be explored when optical images are not available, such as the case of high cloud-coverage of the area of interest. Figure 4: (**a**) Sentinel-2 true colour over the area of interest, (**b**) Radar Vegetation Index (RVI), (**c**) Normalized Difference Vegetation Index (NDVI), (**d**) closer look of (**a**) over the archaeological site of “Nea Paphos”, (**e**) closer look of (**b**) over the archaeological site of “Nea Paphos”, (**g**) closer look of (**a**) over the historical Centre of Paphos town, (**h**) closer look of (**b**) over the historical Centre of Paphos town, and (**i**) closer look of (**c**) over the historical Centre of Paphos town. Vegetated areas are shown with green colour while non-vegetated areas with black colour for the RVI, while for the NDVI vegetation is highlighted with dark green colour. To investigate if any correlation between the NDVI and the RVI values can be established, regression models were applied. Figure 5 shows a scatterplot of 1000 points distributed randomly over the case study area, at different target types, indicating the NDVI and RVI values at the X and Y axis, respectively. As it is shown in this scatterplot, a high variance is observed, indicating that no strong correlation between these two indices can be achieved. This is also aligned with the previous findings, indicating that optical and radar indices do not produce similar findings. In light of the above, monthly RVI and NDVI during the period from May 2019 to May 2020 were extracted from the Sentinel Hub service and interpreted.