## 1 Introduction  
According to the European Landscape Convention (ELC), \"The landscape is part of the land, as perceived by local people or visitors, which evolves through time as a result of being acted upon by natural forces and human beings\" [1]. This definition explicitly emphasizes the interaction between humans and landscape, highlighting landscape characters [2]. Landscape character can be described as \"the presence, variety, and arrangement of landscape features, which give a landscape a specific identity\" [3]. The fact that humans make vital visual connections with the environment is critical in landscape management and planning [4]. There is a large volume of published studies attempting to identify concepts for visual landscape characters. Through experiments, some researchers find that the relative degree of terrain undulation, the number of elements in the landscape, and the landform play important roles [5; 6; 7; 8]. [PERSON] [9; 10] used Landscape Control Points to study landscape characters and visual impacts, concluding with basic design elements such as lines, form, color, and texture. [PERSON] [11] conducted a landscape viewing test on 45 people by varying the richness of the test photos, proposing that the human can see five to seven visual landscape elements. [PERSON] [12] described the dominant attributes of the Dutch landscape as unity, its function, development in time, maintenance, spaciousness, naturalness, soil and water, and sensory qualities such as color and smell. Based on research on landscape perception and evaluation, [PERSON] et al. [13] identified nine key visual concepts which are stewardship, historicity, coherence, disturbance, visual scale, complexity, imageability, naturalness, and ephemera. They proposed a framework of four levels relating to visual character assessment: concepts > dimensions > landscape attributes > indicators. Their identifications of visual characters are comprehensive and consistent with the ELC, which has been used in a few studies [3; 14]. Landscape character assessment (LCA) is recognized as a tool for dynamic management concerning regional identity [15]. Since the 1970s, several methods for LCA have been applied, depending on the different aims of the assessment [16]. [PERSON] and [PERSON] [17] found that there are two main methods for the evaluation of landscape: direct and indirect approaches. Direct methods are applied to compare public preferences for landscape [17; 18], while indirect methods evaluate landscape by analyzing the presence or intensity of designated characters [19]. Similarly, [PERSON] et al. [20] suggest that the aesthetic of landscape comprises both an objective part, which includes physical features, and a subjective part, which involves human perception. When the aim is to analyze the impact of human activities on a landscape, identifiable landscape attributes and physical elements are usually used in an assessment [21; 22]. In visual landscape assessments, three models have been applied widely [23], which are scenic beauty estimation [24], landscape character assessment [25], and visual resource management [26]. For scenic beauty estimation, [PERSON] et al. [16] validated a model including 42 landscape attributes and explored which attributes are the most significant in their evaluations. As for landscape visual characters, landscape indicators provide a more objective basis for identifying features by dividing the totality of our visual perception into quantifiable characteristics [2]. Though visual landscape indicators are less developed than those for other functions of landscape [27], there has been increased emphasis on identifying visual indicators and evaluating landscape visual quality. [PERSON] et al. [14] indicated that the visual and ecological landscape indicators share many common aspects relating to landscape structure.