The board of supervisors may provide and pay from county funds for the making or purchase of the maps and block-books by contract with some other competent person, if any of the following conditions exist:
- (a) The office of the assessor is not provided with maps and block-books.
- (b) The maps or block-books in the office of the assessor are insufficient or defective and the surveyor neglects or refuses to make them.
- (c) The facilities of the surveyor’s office are inadequate to do so.