Any board desiring to change an at-large method of election to a district method of election or from one district method of election to another shall first prepare a plan of change showing the proposed member districts into which the college district will be divided. Each member district shall be comprised of one contiguous compact area. The member districts shall have equal population as nearly as practicable. All of the territory in the college district shall be assigned to and made a part of one of the member districts, and no territory shall be included in more than one member district. The proposed member districts shall be so planned that no member of the board of trustees holding office at the time the change is made will be displaced by establishment or rearrangement of the member districts or by inclusion of more members in a single proposed member district than is authorized by law.