Developing a Hohfeldian theory of Real Rights to support LADM modelling
Channel: Ant Beck
Date: 2022-03-24

The Land Administration Domain Model (LADM cite:[iso_tc211_iso_2012]) is a conceptual model which supports the modelling of social relations with land articulated through _rights_.
There are three principal concepts within LADM: the party (_the who_) that has a rights relationship (_the what_) with a plot of land (_the where_).
A party-right-land model by definition frames rights as property interests in terms of the right holders relationship with land.
In most cases this relationship is interpreted to simply mean ownership.
According to citenp:[williamson_land_2010(88-89)] "_A right is not a relationship between an owner and land.
It is a relationship between an owner and others in relation to land, backed up by the state in the case of legal rights.
This duality of owners and others is also present in restrictions and responsibilities affecting landowners and users.
Each restriction/responsibility involves a duality that imposes obligations on owners in relation to the land for the benefit of others._"
This aligns with Hohfeldian rights theory.
citenp:[hohfeld_fundamental_1917] described rights in terms of their associated privileges, claims, powers, and immunities (see also citenp:[hjelmblom_towards_2019(37-38)]).
Whilst LADM allows such relationships to be expressed, this is not clearly articulated in the standard (citenp:[hjelmblom_towards_2019(52)] provide an excellent overview of these issues).
This is exacerbated by _restrictions_ and _responsibilities_ which frame rights relationships in terms of owned land rather than relationships between parties.

This paper will present a theory of real rights to support LADM modelling.
Each jurisdiction creates a set of ownership and non-ownership rights which are recognised by the state and legally formalised.
This is _numerus clausus_: the limited number of basic land and property rights recognised by the jurisdiction.
The jurisdiction can reserve some of these rights either directly as alienated ownership (reserved property: e.g. minerals and petrochemicals) or indirectly by providing itself with powers to alienate non-ownership rights (which become a Hohfeldian 'duty' and a restrictive overriding interest to all affected owners).
Third parties can permanently or temporarily hold these rights through an express grant, permit, or licence.
These reserved rights, in common with ownership in general, are rights _in rem_ - the rights are good against the world; there is no need to enumerate the duty owing parties for the rights to have affect.

The remaining rights are bundled in to a conventional property ownership concept.
This concept provides immunities and powers to a right holder.
The most important immunity for an owner is _nemo dat_: 'you can not sell what you do not own'.
Powers allow the holder to vary or discharge rights.
Owners can vary their ownership in terms of a party, right or land dimension.
A _party variation_ allows an owner to transfer (sell) all or part of their property.
All such transfers are _in personam_ - the legal instrument which describes the variation specifically identifies the third party grantee who benefits from the rights transfer.
A _rights variation_ allows an owner to alienate rights (such as access) which can then be transferred to third parties.
A _land variation_ allows an owner to split their ownership in to multiple spatial parts some of which can then be transferred to third parties.
These powers are undertaken through the national conveyancing process supported by legal instruments (such as deeds) which legally frame the transactional change.
The transactional legal instruments will be submitted for registration in the national Land Register.

By considering rights, and their associated Hohfeldian attributes, we will describe how generic LADM primitives can be used to articulate the rights duality demanded by citenp:[williamson_land_2010(88-89)].
Party and spatial indexing are critical in articulating such relationships.
This allows _restrictions_ and _responsibilities_ to be modelled in terms of their Hohfeldian incidents in a generic manner that more closely aligns with legal theory.