San Diego (/ˌsæn diˈeɪɡoʊ/ SAN dee-AY-goh, Spanish: [san ˈdjeɣo]; Spanish for 'Saint Didacus') is a city on the Pacific Ocean coast of Southern California located immediately adjacent to the Mexico–United States border. With a 2020 population of 1,386,932, it is the eighth most populous city in the United States and the seat of San Diego County, the fifth most populous county in the United States, with 3,338,330 estimated residents as of 2019. The city is known for its mild year-round climate, natural deep-water harbor, extensive beaches and parks, long association with the United States Navy, and recent emergence as a healthcare and biotechnology development center. San Diego is the second largest city in the state of California, after Los Angeles.
Chengcheng County, which belongs to Weinan City, Shaanxi Province, is located in the eastern part of Guanzhong Basin, Shaanxi Province. It is between 109o 46km east longitude-110o 05km east latitude and 34o 550045 "- 35o 2705km north latitude, with a total area of 1121 square km. Chengcheng County has a long history. It was built from the Northern Wei Dynasty, and the county name has been in use for 1540 years. The terrain is high in the north and low in the south, and the county is divided into "three beams and one original" by four rivers. It is a warm temperate semi-humid monsoon zone with an average annual temperature of 12 ℃, precipitation of 680mm, frost-free period of 204days and a large temperature difference between day and night. As of 2018, Chengcheng County has jurisdiction over 1 street and 9 towns. By the end of 2017, Chengcheng County had a resident population of 393224, with a gross domestic product (GDP) of 8.569 billion yuan.