Land use regulations must be uniform throughout the district except that the supervisors may classify the lands within the district with reference to such factors as soil type, degree of slope, degree of erosion threatened or existing, cropping and tillage practices in use, and other relevant factors, and may provide regulations varying with the type or class of land affected but uniform as to all lands within each class or type. Copies of land use regulations adopted under this chapter must be printed and made available to all qualified electors living within the district.