## 4 Results
### Regional Preferences' Analysis at the Local Level  
After the analysis of tourism dynamics at the regional level, and the clusters' and the spots' identification in terms of successful destinations through the tourists' preference patterns, we considered the tourist destination of Cagliari for further analyses. Cagliari, the capital city, is located in Southern Sardinia. It is nationally and internationally well connected thanks to the airport, the port, and the marina. Cagliari is the most important municipality in terms of trade and demographic size. Indeed, 50% of the Sardinian air traffic is related to the airport, with about 4 million passengers per year [33]. Records of our 2012-2013 database indicate that TLSs located in Cagliari are considered among the best-selling destinations by different tourists' typologies. Figure 2: Clusters of tourists’ positive preferences incidence (TPPI). The map in Figure 3 shows the spatial clusters of preferences. The location of each TLS immediately allows one to detect which sites the preferences of tourists who visited Cagliari are focused on; thus, it is possible to answer questions such as, \"What areas, sites, or artifacts attract the tourists' attention?\" Spatial clusters of preferences are detected by hot-spot analysis. Firstly, a threshold distance of 1700 m was identified and the spots by census tract summarized. The map in Figure 3 shows the spatial distribution of values of TPPI; the red areas, located in the inner areas of the municipality, show high concentration of the TPPI phenomenon (hot spot), while the blue areas represent locations where the phenomenon is less intense (cold spot). Not surprisingly, the inner areas of Cagliari attracts tourists while Pirri, a peripheral residential area of the Cagliari municipality, represents a cold spot. The next step focuses on each review's content in order to understand not only \"where\" but also \"what\" tourists think about Cagliari. Hundreds of textual reviews have been investigated through STTx analysis. The opportunity of analyzing the tourists' preferences may help assess the spatial patterns related to attractive TLSs in order to detect useful hints to be used for the definition of planning policies in terms of tourism development at the local scale. Very interesting results have been obtained by applying STTx to local subsets of data obtained by selecting high TPPI values based on TLSs' locations. The tag cloud (Table 1) clearly shows that the majority of the words in the posts refer to spatial or physical aspects of the municipality, such as \"center\", \"city\", \"location\", and \"church\". \begin{table}
\begin{tabular}{c c} \hline
**Category** & **Words (frequency)** \\ \hline Geographic location & location (1010); town (476) \\ Service & staff (890); restaurant (643); room (459); hotel (469); pool (230); food (180) \\ Accessibility & minutes (250); harbor (237); proximity (164); walking (146) \\ \hline Natural and non & city center (426); beach (378); old city (132) \\ natural components & \\ \hline \end{tabular}
\end{table} 
Table 1: Top 15 words related to Cagliari divided by category. Figure 3: Significant patterns in Cagliari municipality. The results include keywords related both to leisure sites, such as \"restaurants\", \"shopping\", and \"dinner\", and to services, such as \"staff\" and \"room\". Moreover, the outcomes indicate that a high level of satisfaction is related to accessibility: words as \"minutes\", \"proximity\", and \"walking\" could be related to the services' spatial location, natural resources or monuments. So, ease of movement from one site to another generates a positive tourist destination image. In addition, different sectors within the local community could benefit from the presence of tourists. Business sectors are more likely to hold favorable views on tourism because of the economic benefits it is perceived to bring.