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.
Nangqian County, which belongs to Yushu Prefecture, Qinghai Province, is located in longitude 95 °21 "58" ~ 97 °07 "0" east and latitude 31 °32 "20" ~ 32 °43 "46" north. It is adjacent to Haixi Mongolian Tibetan Autonomous Prefecture in the north, Guoluo Tibetan Autonomous Prefecture in the east, Ganzi Tibetan Autonomous Prefecture in Sichuan Province to the southeast, and Changdu in the Tibet Autonomous region to the south. The longest is 157.5 kilometers from east to west, and the widest from north to south is 130.5 kilometers, with a total area of 12741 square kilometers. In 2013, the total population of Nangqian County was 130000, including Tibetan, Han, Hui, Tu and other ethnic minorities. Nangqian County has gold, silver, copper, iron, lead, zinc, tin, gypsum, sulfur, limestone, coal, salt and other mineral resources. In 2013, the gross domestic product of Nangqian County reached 7.449 billion yuan.