The department shall investigate and prepare a complete report on mapping, including plans and recommendations for an adequate mapping program for California, and shall adopt a general plan and program for the accomplishment of the policy declared in this chapter. The general plan and program so adopted, or as amended or modified, shall be the authorized general plan and program to be carried out by the department. The department may from time to time make such further investigations and reports upon mapping as deemed proper by it in pursuance of the policy declared in this chapter.