locater
/lə(ʊ)ˈkeɪtə/noun
1Originally and chiefly US. A person who makes a claim to land or mining rights, or takes up a grant of land, by establishing and registering the boundaries of the claim or grant.
2Something which locates; a device or system used for determining the position or location of something; = locator.
Origin
Early 19th century. From locate + -er.