Quanhu Road, Maiji District, Tianshui City, Gansu Province. According to the Baidu map, Tianshui Huizhi Information Surveying and Mapping Co., Ltd., located in Quanhu Road, Maiji District, Tianshui City, Gansu Province, is mainly engaged in gps surveying teaching and surveying and mapping business. Global Positioning System (GPS) is a high-precision positioning system for radio navigation based on artificial earth satellites.