Ohio coordinate system would use statewide and county-based zones

Ohio’s coordinate system is described as having one statewide zone and a set of smaller zones based on county boundaries. The smaller zones together cover the same area as the statewide zone.

The text specifies which foot measurement to use for certain coordinate and height conversions. These rules apply to foot measurements used in horizontal coordinate systems and orthometric heights. Use the international foot for horizontal coordinates tied to 2022 or later datums, and for heights tied to the North American Pacific geopotential datum using 2022 or later datums or adjustments. Use the U.S. survey foot for horizontal coordinates tied to earlier datums and for heights tied to legacy vertical datums or adjustments. The distinction depends on whether the referenced datum or adjustment is from 2022 or later, or is earlier or legacy.

Survey documents using Ohio coordinates or orthometric heights must identify the relevant zone, datum, dates, and measurement details. The requirements apply to land descriptions, plats, maps, survey reports, and other documents that use Ohio coordinates or orthometric heights.