Classification and Coding of Entity Features for Digital Twin Sichuan-Tibet Railway

The heterogeneous multidisciplinary spatial information data with multi-granularity and sophisticated semantics of features in the wide area of Sichuan-Tibet railway, which leads to the inconsistency of data content/format and spatio-temporal datum.Therefore, it is difficult to integrate/analyse relevant data efficiently. In order to establish the concept system of cognitive sharing for the unified expression of spatial information of Sichuan-Tibet railway, firstly, this article has studied and depicted the geometry, scale, topology, attribute, behavior characteristics and interactive relationship of different feature types such as "geography""geology""facilities""meteorology""ecology""disaster" and "personnel"; secondly, according to the framework of relevant national standard classification and coding system, the study has regulated the unified coding rules and expanding methods, conducted substantialization classification upon various feature types into the minimum management unit. Based on the rules, the classification in higher level (primary category, subcategory, large class and medium class) and the classification in lower level (level Ⅰ, Ⅱ and Ⅲ subclasses) was expanded and reduced according to the application requirements of Sichuan-Tibet railway respectively, leaving 2 primary categories, 6 subcategories, 27 large classes and 87 medium classes in total. On this basis, each feature entity in the classification system was coded and given a unique and unambiguous identity, so as to implement the precise mapping between three-dimensional spatial information and feature entities and provide support for the construction of Sichuan-Tibet railway.