In Coordinate System table, field COORD_SYS_TYPE, added 'vertical' to value list and amended description. (Historic type 'gravity-related' retained as allowable value to accommodate existing user data). For CS 6496-99 changed CS type from 'gravity-related' to 'vertical'. In edit/add coordinate system form, added 'vertical' to value list, changed 'multi-linear' to 'linear'. Help forms updated. (Edit/add Form now limited to current valid subtypes).