The semantic relation of ‘source’, expressed by the prepositions 由/从+NPloc ‘yóu/cóng +NPloc’ (from…), often involves position and direction:
Tā cóng jiā xiàng shān xià de xuéxiào zǒuqù.
(He walked toward the school down the hill from his home.)
In (1) the prepositional phrase 从家‘cóng jiā’ (from home) denotes the notion of source or the point of departure of the action of 走‘zǒu’ (walking), the semantic relation of direction involves position: ‘on the hill’, and direction: towards the bottom of the hill.
 Loar, J. K. (2011). Chinese syntactic grammar: functional and conceptual principles. New York: Peter Lang.