The modelling of rights, restrictions and responsibilities (RRR) in the land administration domain model (LADM)

Abstract

In this paper, the modelling of alternatives for Rights, Restrictions and Responsibilities (RRRs) are discussed, within the context of the Land Administration Domain Model (LADM, ISO 19152, under development). This includes the modelling of holding shares in a RRR. LADM currently provides for the aggregation of objects into explicit ‘group objects’ with regard to (a) people and organisations (class LA_Party), and (b) parcels (class LA_SpatialUnit). This aggregation facility is not available for the RRRs. In case of RRRs it was recognized that these objects (as smallest units) should together form a ‘whole’; e.g. two different persons, both having a ½ ownership right on the same parcel. This is enforced in the current LADM by a constraint, performing this check. In this paper two model alternatives are explored: (1) in one alternative the model was extended by an explicit class LA_RRR_Group, (2) in another alternative no new classes where introduced in the model, but the relevant constraint was refined. Especially, representing the case of multiple easements on a single parcel, without their own easement geometry (the ‘negative’ side), with each easement benefiting multiple parties (the ‘positive’ side), is challenging with respect to the possibility to group the various easement-‘shares’ (‘parts’) into a ‘whole’. This paper shows that even this case can be represented well in the current LADM (including the refined constraint). However, it is easier to model this situation in the extended LADM with the new class LA_RRR_Group, but at the cost of complicating the model and the registration of all RRRs (while most of them not do need this extension at all). The conclusion (at least for the time being) is, that this complication of extending the LADM with an additional class LA_RRR_Group, is not worth the benefit and that therefore class LA_RRR_Group will not be included in the next version of the LADM.