**1.2.4 Spatial database**

According to the railway GIS platform design, the data layer is composed of the maintenance of spatial databases and spatial data management subsystem [10].

Railway spatial database is composed by the railway common spatial data, and spatial data can be shared professional and metadata.


Digital Railway spatial database can be divided into three parts by their contents, which are the national common geographic information data, the railway geographic information data and the sharable railway professional GIS data.

The spatial data maintenance and management sub-system is responsible for the management of the spatial data and metadata, which are stored in geographic information platform, including geographic information platform model and spatial data management, spatial data (vector and raster data) to import, export, convert, copy, append; spatial data quality control, network topology and relationship maintenance; incremental replication and exchange of spatial data; spatial data metadata management, including meta-data collection, management, publishing and navigation.
