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.
Ruoergai County, which belongs to Aba Tibetan and Qiang Autonomous Prefecture, is located on the northeast edge of the Qinghai-Tibet Plateau, located in the north of Sichuan Province, and is the north gate of Sichuan to the northwest province. the geographical coordinates are between 102 °08'E and 103 °39'E and 32 °56'N to 34 °19'N, bordering Maqu County, Luqu County, Zhuoni County, Diebu County and Neiaba County, Hongyuan County, Songpan County and Jiuzhaigou County of Aba Prefecture, respectively. The Yellow River and the Yangtze River divide it into east and west parts. The maximum distance between east and west and north and south is about 150 kilometers. It is 475.3 kilometers away from Lanzhou, 322.4 kilometers away from Markang, the capital of the state, 469.2 kilometers south from Chengdu, and 3406 meters above sea level. Ruoergai County covers an area of 10436.58 square kilometers. At the end of 2010, Ruoergai County