Developing the electronic digital map of ground conductivities of China

The electronic digital map of ground conductivities is very important and useful to radio systematic engineering such as time service, navigation, communication and broadcast, etc. ITU-R recommended that the map of ground conductivities be surveyed, studied and standardized. The process of investigating and developing the electronic digital map of ground conductivities of China is introduced in this paper. The key techniques and methods for making the map, especially, the map data auto-collecting by scanning and the computer graphics are described in detail. The electronic map of ground conductivities of China (version 1.0) has been completed and is shown. Additionally, the usage of this electronic map is explained.