Good question with no simple answer. CLIs and CLRs typically include an inventory of historic features, and an assessment of their condition, integrity and significance. The CLR typically also includes recommendations for treatment of the resource, which is useful to those responsible for managing a landscape. Treatment recommendations can also help guide how best to implement needed changes to a historic property in a manner that will minimize impacts on historic features. HALS is the only form of documentation that is accessible to the public.
Government agencies and private property owners use CLIs and CLRs as guides to managing their property. Since 1966, the National Historic Properties Act (NHPA) has mandated that all federal projects or projects using federal money be required to prepare a CLI or CLR when impacts to resources are unavoidable.
HALS is similar in some ways to CLI and CLRs. HALS is intended to be a comprehensive, scholarly record of a landscape. The historic narrative provides a description of the history of the landscape. The measured drawings depict what the landscape looks like when the documentation is done. HALS photographs record what the landscape looks like when the photographs are taken.