## 4 Discussion and Conclusions  
Social media data, especially photographs, has become a new form of evaluating landscape visual indicators [46]. This article highlights the considerable potential of uploaded photographs for public perception analysis and landscape visual quality assessment. Through photograph content analysis, a deep comprehension of what observers portray can be applied to exploring the landscape attributes which attract people. The major discoveries of the present study are as follows:  
* In line with prior studies on landscape preference and visual landscape assessment based on traditional data and social media data [47; 74], which suggest a positive relation between landscape diversity and observer's perception, this article confirms that the complexity of landscape attributes is a determining factor related to landscape visual quality. However, as people tend to have different preferences towards different landscape types [75], this finding related to cultural landscapes is slightly inconsistent with previous studies on ecological landscapes. Complexity affects both  
Figure 8: Point density analysis of trajectory data. the effort required to perceive the object and the amount of information in a landscape scene. In terms of ecological landscapes, the inverted-U-shaped relation between complexity and landscape preference has been proved in many papers [65]. As for cultural landscapes, the elements for visual quality in urban settlements range from the whole of the city to its parts, such as a boulevard or a street [76]. Among the urban landscape indicators, building facades serve as a vital feature providing important information [77]. Thus, this research innovatively selects camera angles reflecting different facades of attractions as landscape patches, which could be a valuable application to assess the complexity of cultural landscapes. The Old Dormitory in the study area has the maximum value of PRD, which suggests that visitors can have the richest observation points around this attraction. * The results about saturation and hue values corroborate the findings of a great deal of previous work in visual elements accounting for people's preferences [16; 47; 54; 77]. With high AMS and SDH values, observers are willing to stay and obtain picturesque images at the Old Dormitory and College of Engineering. This finding is consistent with the results in the investigation by [PERSON] and [PERSON] [75], in which high color variation and chroma have positive correlations with preference and encourage visual fixation. Nonetheless, contrast can be perceived differently. According to [PERSON] et al. [54], incompatible contrasts might lead to poor integration into the environment, such as color contrast in urban signposting. Conversely, the preference for visual beauty has a positive correlation with color contrast in [PERSON] et al. 's work [21]. This study supports the finding of [PERSON] et al., which indicates that the color contrast existing in the study area is incompatible. With low values of contrast, Wuhan University Library, the Old Dormitory and the College of Engineering provide a sense of wholeness in the landscape. * As for the results about visual scale, depth of view has a relatively minor impact on perceived visual quality. With close-up photos accounting for about 50% of the total photos, the uploaded photographs contain mainly close-up views, which indicates that observers tend to appreciate these landscapes at a close distance. However, this outcome is contrary to that of [PERSON] and [PERSON] [68], who found that distance to the back ridge was much more predictive of scenic beauty than the distance to the front ridge, and there was a concave upward relationship between distance and preference. A possible explanation for these results may be that cultural landscapes are perceived differently from natural landscapes.