Why was the mission san luis obispo built in its location?

. They named the area La Cañada de los Osos or Valley of the Bears. 

The Spanish eventually realized that the “Valley of the Bears” had a large amount of food and other natural resources and that the local tribe, the Chumash, were friendly. They decided that it would be a good location for another Mission. The Mission is located a few miles from the coast in a protected valley with good land for farming. 

Mission San Luis Obispo de Tolosa is a Spanish mission founded in 1772 by Father Junípero Serra in the present-day city of San Luis Obispo, California. Named after Saint Louis of Anjou, the bishop of Toulouse, the mission is the namesake of the city of San Luis Obispo and San Luis Obispo County.I hope it helps