It is the purpose of this chapter to regulate and control the division of land within the City and to supplement the provisions of the State Subdivision Map Act concerning the design, improvement and survey data of subdivisions, the form and content of all maps provided for by the State Subdivision Map Act and the procedure to be followed in securing the official approval of the City of Sebastopol regarding such maps. The intent of this chapter is to encourage orderly development and to ensure that appropriate public improvements are provided. To accomplish these purposes, the regulations outlined in this chapter are determined to be those reasonably necessary for the preservation of the public health, safety, and general welfare, to promote orderly growth, development, open space, conservation, protection and proper use of land, and to ensure provision for adequate traffic circulation, utilities and services and to promote and implement the General Plan. The requirements of this chapter are in addition to all other requirements.