Verb
pitch upon (third-person singular simple present pitches upon, present participle pitching upon, simple past and past participle pitched upon)
To choose, to pick, to fix one's choice on something or someone.
More generally, the tonic is the pitch upon which all other pitches of a piece are hierarchically referenced. Source: Internet
In this case, the lineation may be measured from the horizontal as a rake or pitch upon the surface. Source: Internet