**4. Discussion**

The landscape variables or indicators represent the spatial patterns of the entire landscape mosaic [35]. The classification of the landscape character of the variables (or indicators) by the clustering method can clearly explain the landscape, which is conducive to capturing its abundance and uniqueness [7]. At present, progress has been made in multiscale research on landscape character. There are large-scale studies using national, regional, and local scales or large, medium, and small scales, regardless of the administrative scales, as well as studies using the region, corridor, and settlement scales [26,36,37]. On the basis of previous studies, in this paper we selected a combination of holistic and parametric methods to divide the two-scaled landscape character of the Yunnan–Vietnam Railway (Yunnan section) by considering the correlations, dimensional differences, and data mixture attributes of the landscape variables.

Our results showed that there 11 landscape character types and 80 landscape character areas at the regional scale and 12 landscape character types and 58 landscape character areas at the corridor scale. Landscape character types and areas were quite diverse in the different areas and scales for the different data sources, clustering methods, and identification modes [38]. For instance, Chongming Island in Shanghai was divided into 6 landscape character types, 18 landscape character sub-types, and 87 landscape character areas [39], while there were 17 landscape character types and 192 landscape character areas in Wuyishan National Park [40].

The landscape character types of the heritage railway were dominated by "L3L4, V1V5V8V10, S5, H7 G4L3, V5, G4" and typical in "{L3L4}, {V4V5V7V8}, {S5S14}, {G1G3G8G12G15G16}" at the regional scale, and were dominated by "α4, β1β2β3, γ4γ5, θ2θ4, ε1ε2" and typical in "{α3α4}, {β1β2β3β4}, {γ2γ3γ4γ5}, {θ1θ2}"at corridor scale. We took the prominent and typical characteristics as the basis for the division and description of landscape character areas, which is similar to previous research [41,42]. The main difference was that we analyzed the general characteristics. In addition, the ratios of the landscape indicators to the variables were closely related to the landscape character types. The higher the ratios, the more likely they were to be prominent or typical landscape types. The ratio of the red earths indicator to the soil variable was 55% at the regional scale and that of the forest land indicator to the land use variable was 58% at the corridor scale, both of which were prominent or typical features in the landscape character types at each scale. This was confirmed by the results of

Li's study on the landscape character of traditional settlements in the Wuling Mountain area at the regional scale [37]. Thus, landscape character types can be used to represent the ratios of the landscape indicators to the variables, which is of great importance for studying the spatial mosaic patterns of linear heritage landscapes and the data mining of resource features.

The spatial distribution of landscape character areas indicated that the landscape character areas were more distributed when closer to an urban area and vice versa. At the regional scale, the distribution of the landscape character areas in Kunming City and Yuxi City was relatively compact, while the distribution of the areas in Honghe Hani and Yi Autonomous Prefecture and Wenshan Zhuang and Miao Autonomous Prefecture was relatively sparse. The landscape character areas gradually decreased in number from north to south. At the corridor scale, the distribution of the landscape character areas in Kunming City, Jianshui County, Mengzi City, Kaiyuan County of Honghe Hani, and Yi Autonomous Prefecture was relatively compact, while the distribution in other areas was sparse. This was mainly because the areas were divided according to landscape character types and field survey. Urban areas contained more landscape types and more diverse combinations. For example, in urban areas there were landscape character areas characterized by water areas, arable land, and built areas, while the natural areas were dominated by forest land at the corridor scale. In addition, the concentration of the heritage railway was primarily in urban areas, which could also be divided into landscape character areas with mediumand low-heritage densities. The distribution of industrial heritage in natural areas was relatively sparse, making it difficult to form a heritage agglomeration area. The spatial distribution features of the landscape character areas could provide basic references for railway revitalization in each administrative region.

The two-scaled identification of landscape character provides a baseline for redefining the complex boundaries of the Yunnan–Vietnam Railway (Yunnan Section) and a framework for better management, planning, and judgement with respect to the landscape. The main limitations of this paper are two-fold: on the one hand, we adopted a top-down method for identifying the landscape character, ignoring public perceptions [43–45]; on the other hand, our study did not address landscape decisions. In future research, more detailed hierarchical identification involving public perceptions and landscape decisions should be realized.
