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.
Qin'an County, which belongs to Tianshui City, Gansu Province, is located in the southeast of Gansu Province, the north of Tianshui City, and the lower reaches of Hulu River, a tributary of Weihe River; the center is located at 34 °51 °N and 105 °40 °E, with a total area of 1601 square kilometers. As of 2015, Qinan County has jurisdiction over 12 towns and 5 townships. The total population is 618000 (2012). In 2015, the GDP of Qin'an County reached 5.26 billion yuan. Qinan County belongs to the temperate semi-humid climate in the south of Longzhong, with an annual average temperature of 10.4 ℃ and a normal annual precipitation of 507.3 mm. Qin'an County is one of the eighteen arid counties in Gansu Province, which belongs to the Liangfeng gully region in the west of Longzhong Loess Plateau with many mountains and few rivers. By 2015, Yangshao, Majiayao, Qijia Culture and other Neolithic cultural sites have been found in Qin'an County.