Whenever the land involved in any subdivision is of such size or shape or is subject to such title limitations of record or is affected by such topographical location or conditions or is to be devoted to such use that it is impossible; impractical or undesirable in a particular case for the subdivider fully to conform to the regulations contained in this title; the planning commission may recommend and the city council may permit such modification thereof as may be reasonably necessary if the modifications are in conformity with the spirit and purpose of the Subdivision Map Act and of this title. Application for any such modification shall be made by a verified petition of the subdivider; stating fully the grounds of the application and the facts relied upon the petitioner. Such petition shall be filed with or after the filing of the tentative map of the subdivision. In order for the property referred to in the petition to come within the provisions of this chapter; it is necessary that the planning commission finds the facts designated in Sections 20.40.020 through 20.40.040 with respect thereto. (Ord. 1046 NCS §1 (part), 1972; prior code §22.9.100.)