Extending Land Administration Domain Models with a Goal Perspective

Christophe Ponsard

and Mounir Touzani

CETIC Research Centre, Charleroi, Belgium

Acad

emie de Toulouse, Toulouse, France

Keywords:

Cadastral System, Land Registration, Spatio-temporal Modelling, Goal-oriented Requirements Engineering.

Abstract:

Land administration covers many complex processes for managing rights over land, estimating value, gather-

ing revenues and regulating land use. Its organisation typically relies on land registration and cadastre. Over

the years, elaborated domain models have emerged and have been standardised. While those models address

many dimensions of this domain, they fail to capture the rationale behind the design of the model or leave

it quite implicit. In this paper, we propose to augment such domain models with a goal dimension in order

to provide better guidance in the design of new systems and better understanding of existing systems, espe-

cially in the perspective of driving the wide variety of E.U. systems to evolve towards more interoperability.

Our work relies on the KAOS goal-oriented framework for system design and highlights the use of sound

structuring and reasoning techniques.

1 INTRODUCTION

The term land administration (LA) was deﬁned by the

United Nations Economic Commission for Europe as:

“the process of determining, recording and dissemi-

nating information about ownership, value and use of

land and its associated resources. These processes in-

clude the determination (sometimes called ‘adjudica-

tion’) of land rights and other attributes, their survey

and description in a detailed documentation, and the

provision of relevant information for supporting land

markets” (UNECE, 1996).

The key LA concepts were identiﬁed by

(Henssen, 1995) and are shown in Figure 1.

The owner (“Who”) and parcel (“Where”/“How

much”) concepts are connected by a Right relation-

ship which is often generalised into “triple-R” for

Right/Restriction/Responsibilities (for the “How”).

Figure 1: Key domain concepts (Zevenbergen, 2004).

Those concepts form the core of reference do-

main models such as Core Cadastral Domain Model

(CCDM), the Land Administration Domain Model

(LADM, ISO 19152) and the Social Tenure Domain

Model (STDM). Those models are discussed and

compared in section 2. The processes managing those

concepts are usually split across the following two

systems which can be managed by a single or differ-

ent organisations (Henssen, 1995):

Land registration deals with the ofﬁcial recording

of rights on land concerning changes in the legal sit-

uation of deﬁned parcel. It can be organised either

through deed or title registration, with a progressive

transition to the second option observed in many E.U.

countries (Yavuz, 2005). This covers the “Who” and

“How” questions.

Cadastre maintains a comprehensive public in-

ventory of data concerning properties of a country or

district. It is based on a survey of their boundaries and

value. It gives an answer to the questions “Where”

(spatial dimension) and “How much” (both for own-

ership transfer and taxation purposes).

The mentioned domain models essentially provide

a reference vocabulary (or ontology) for describing

the complex data (rights, geometry of parcels,...) in-

volved LA. Such models support the development and

interoperability between LA systems in an efﬁcient

way. However, they are less good at driving the de-

sign of new systems or at understanding the rationale

behind the design of existing systems. The reason is

that the “Why” dimension of the different model fea-

244

Ponsard, C. and Touzani, M.

Extending Land Administration Domain Models with a Goal Perspective.

DOI: 10.5220/0006350202440249

In Proceedings of the 3rd International Conference on Geographical Information Systems Theory, Applications and Management (GISTAM 2017), pages 244-249

ISBN: 978-989-758-252-3

tures are currently not explicitly captured but it would

be worth being supported because:

• E.U. member countries have all deployed their

own LA systems. Although they follow similar

principles they are not harmonized at all which

is the long term goal to achieve for the E.U. An

overview of all European systems has already

been carried out as well as some targeted com-

parative work (Yavuz, 2005)(EU PCC, 2009).

• main LA actors (FIG/World bank) are increas-

ingly stressing that LA systems should be “ﬁt-for-

purpose” rather than blindly complying with com-

plex technological solutions and rigid regulations,

i.e. LA should be designed to meet people’s needs

and relationship to land in a sustainable way (En-

emark et al., 2014). This is especially for devel-

oping countries (Williamson, 2000).

This paper aims at proposing an extension to ex-

isting domain models that explicitly address the miss-

ing goal dimension. In order to achieve this, we apply

methods and notations from the goal-oriented require-

ments engineering ﬁeld (van Lamsweerde, 2001).

This work also applies speciﬁc spatio-temporal an-

notations for guiding in structuring and reasoning on

goal models (Touzani and Ponsard, 2016).

This paper is organised as follows. Section 2

presents and compares three main domain models for

LA. Section 3 details the goal-oriented framework ap-

plied to extend the existing models with explicit goal

and responsibility modelling. The extension itself is

detailed in section 4 while section 5 discusses some

related work. Finally section 6 draws conclusions and

gives some perspectives to further extend this work.

2 REVIEW OF DOMAIN MODELS

2.1 Core Cadastral Domain Model

The Core Cadastral Domain Model (CCDM) was pro-

posed at the FIG 2002 Congress. It broadly covers

land registration and cadastre. It provides an extensi-

ble ontology supporting the sound design of a cadas-

tral system using a model-driven architecture that re-

lies on that shared model. CCDM Version 1.0 was

presented in 2006 and also included 3D aspects (Oos-

terom et al., 2005). The core model is depicted in Fig-

ure 2 which is very close to the abstract model of Fig-

ure 1. CCDM concepts also carry explicit identiﬁers

and date attributes enabling traceability and temporal

reasoning.

Figure 2: Overview of CCDM.

2.2 Land Administration Domain

Model

The Land Administration Domain Model (LADM) is

a conceptual model, and not a data product speciﬁca-

tion. It is meant to be a descriptive standard and not

a prescriptive one. Domain speciﬁc standardisation

is needed to capture the semantics of the LA domain

on top of the agreed foundation of basic standards for

geometry, temporal aspects, metadata and also obser-

vations and measurements from the ﬁeld. The LADM

goals are to establish a shared ontology, support de-

velopment of related software, facilitate the exchange

of data and provide support for quality management

in LA (Lemmen et al., 2015). It has been standard-

ised under ISO 19152 (ISO, 2012).

LADM is quite elaborated and has very detailed

specialisation hierarchies for all the LA concepts.

Figure 3 is a reﬁnement of Figure 1. Owner and Par-

cel are the LA Party and Spatial Unit respectively lo-

cated in the top left and bottom right cornet while the

rest of the concepts presented details different kinds

of Rights/Restrictions/Responsibilities (RRR).

Figure 3: Overview of LADM.

Extending Land Administration Domain Models with a Goal Perspective

245

2.3 Social Tenure Domain Model

The Social Tenure Domain Model (STDM) is a vari-

ant of the LADM that presents a generic and inclusive

solution. It was released in 2014 together with Open

Source tools with the aim to help in building ﬂexi-

ble land administration systems. For this purpose, it

proposes a modelling of relations that is independent

from their level of formalization and/or legality. For

example, it supports all forms of land rights including

customary and informal rights as shown in Figure 4

borrowed from (Christl et al., 2015).

Figure 4: Overview of STDM.

2.4 Comparison

The above models are compared in Table 1. LADM

and STDM column show extra (+) features w.r.t. the

previous column. In short, LADM is the standard and

covers CCDM while STDM is a less formal variant.

For sake of simplicity, this paper will use CCDM.

Table 1: Comparison of main LA domain models.

Concept CCDM LADM STDM

Owner Natural

person

+group

+cooperative

+company

+municipality

+couple

Property Parcel,

building,

ways

+land

surveys

+text descr.

+unstruct. lines

+3D volume

Rights Formal

ownership

+Restriction

+Responsib.

+special rights

(e.g. hunting)

3 METHOD: GOAL-ORIENTED

SPATIO-TEMPORAL ANALYSIS

Goals capture, at different levels of abstraction, the

objectives the system under consideration should

achieve. Goal-Oriented Requirements Engineering

(GORE) is concerned with the use of goals for elic-

iting, elaborating, structuring, specifying, analysing,

negotiating, documenting, and modifying require-

ments. To support our research, we focus on KAOS,

a speciﬁc GORE method (van Lamsweerde, 2009).

However, the same concepts and methods can be ap-

plied in other GORE variants like i* (Yu and My-

lopoulos, 1997) and GRL (ITU, 2012).

The KAOS method is organised in four sub-

models graphically depicted in Figure 5:

• The goal model structures functional and non-

functional goals. It also helps to identify related

conﬂicts and reason about their resolution. It is

graphically represented as a goal tree which can

also capture system design variants.

• The object model deﬁnes and interrelates all con-

cepts involved in goal speciﬁcations. Its represen-

tation is aligned with the UML class diagram.

• The agent model identiﬁes the agents of both the

system and the environment as well as their inter-

faces and responsibilities. They can be shown as

part of goal trees or in more speciﬁc diagrams.

• The operations model describes how agents

functionally cooperate to ensure the fulﬁlment of

their assigned requirements and hence the system

goals. Functional ﬂow diagrams are used here.

Figure 5: KAOS Meta-model.

Reasoning on both space and time is important

as Geographic Information Systems (like LA) and

Cyber-Physical Systems are increasingly developing.

For this purpose, speciﬁc notations depicted in Fig-

ure 6 have been integrated into the goal and object

models together with a set of patterns and heuristics

guiding in the discovery and structuring of goals, e.g.

spatial and temporal reﬁnement patterns, quantitative

reasoning, transposition across domains, etc.

Figure 6: Space-time pictograms.

GISTAM 2017 - 3rd International Conference on Geographical Information Systems Theory, Applications and Management

246

4 GOAL-AWARE MODEL FOR

LAND ADMINISTRATION

This section provides excerpts of the goal-

oriented model with the aim to illustrate its

global structure and systematic building tech-

niques. The full model is available online at

doi:10.13140/RG.2.2.21197.84969. It was build

using the Objectiver toolset (Respect-IT, 2005).

4.1 Capturing the Relevant Vocabulary

In a goal-oriented context, the object model aims at

gathering and structuring the vocabulary required for

expressing goals. It can be built iteratively together

with the goal model. We could validate that the

CCDM model ﬁts this purpose. In our modelling,

depicted in Figure 7, identiﬁers and time intervals

during which an entity exists have also been explic-

itly modelled with more meaningful names (e.g. da-

teOfDeath for a person, dateOfExpiration for RRR).

Concept specialisations were detailed here but are

similar to those available in existing domain models.

We also used spatio-temporal decorators to tag the di-

mensions that are present in each concept.

Figure 7: Object Model.

4.2 Capturing Strategic Goals

The top goals of our system modelling are of strategic

nature and are depicted in Figure 8. Those goals are

also aligned with strategic goals and responsibility as-

signments published in key literature references such

as (Enemark, 2001) and (Zevenbergen, 2004). The

diagram should be read vertically with more abstract

goals at the top and more operational goals at the bot-

tom and following yellow reﬁnement nodes connect-

ing goals with their sub-goals. So going up/down re-

spectively means asking “Why?”/“How?”.

The goal introduced at the top is about sustainabil-

ity which has three dimensions: ﬁnancial, social and

environmental which can be identiﬁed in later sub-

goals. However, the ﬁrst reﬁnement is based on the

classical functional versus non-functional distinction.

The former is called “effectiveness” and covers main

functions related to the planning and enforcement of

land use. The later is called “efﬁciency” and is ex-

pressed in terms of legal protection and value man-

agement, covering both citizen aspects (e.g. for prop-

erty transfer) and the public authorities (e.g. for col-

lecting taxes).

Figure 8: Strategic Goals.

Further reﬁnements are not fully detailed. How-

ever a major observation is that they all rely on two

key subsystems: land registration and cadastre. The

rationale between this decomposition is based on in-

formation control. Looking at the object-model:

• land registration is controlling the Right/Restric-

tion/Responsibility relationship, and consequently

many related contractual and legal aspects.

• cadastre is controlling the RealEstateObject, es-

pecially its classiﬁcation, associated topographic

characteristics and the associated value.

• an external system, the Population Register, man-

ages the Person information.

4.3 Robust Design Rationales

High-level goals assigned to sub-systems can be fur-

ther reﬁned to make explicit all the relevant require-

ments. Different techniques can be used to provide

some assurance of completeness and robustness:

• reﬁnement patterns drive goal decomposition to-

wards completeness with rationales. Some com-

mon patterns are temporal milestones and case-

based decomposition.

• obstacle analysis enables the identiﬁcation of un-

desired behaviours and mitigate them by making

existing goals more realistic or by the introduction

of goals correcting or anticipating obstacles.

Figure 9 shows the reﬁnement of the main cadas-

tral goal Maintain[Real Estate Object Known and

Kept Up-to-date]. The left part of the reﬁnement is

a milestone pattern composed of three key steps con-

trolled by different agents. However this design does

Extending Land Administration Domain Models with a Goal Perspective

247

not allow to detect changes that occur outside of a

transaction, e.g. when some work increases the cadas-

tral rent. To address this, the right goal introducing a

periodic systematic assessment is introduced. How-

ever, this goal might suffer from other obstacles, as

detailed in the next section.

Figure 9: Modelling cadastre updates.

4.4 Capturing Design Variability

Although systems are developed to fulﬁl common

strategic goals, the fact they where historically de-

signed in different countries implies that there is a

large variability in the way those goals are imple-

mented in national systems. We review here the main

variability points (Bogaerts and Zevenbergen, 2001):

Deed Registration Versus Title Registration. Deed

registration is based on the transaction document

(with rules like: an older document prevails) and thus

provide no guarantee of the title. Title registration

means the right is really associated to the parcel and

can be guaranteed. Both systems are modelled in Fig-

ure 10. Two distinct reﬁnements are used at the top

of the diagram. Each alternative is further reﬁned and

analysed.

Figure 10: Modelling the titles vs deeds alternatives.

In the deed-based systems the main obstacle (in

red) is that deeds can be questioned and introduce

a conﬂict with the strategic goal of legal protection.

In a title-based system, the registration process must

be careful and might induce long processing times or

even frozen titles. The tendency is to move to title

guarantee but could still rely on an underlying “deeds

system”, thus combining both alternatives. So the dis-

tinction is evolving towards positive versus negative

systems, given they provide or not a guarantee.

Land Registration and Cadastre Components Sep-

arated or Integrated: within the same organisa-

tion. Given their close interrelation, those compo-

nents should ideally be integrated. However for his-

torical reasons, they might have been developed inde-

pendently with some data replication. Different tech-

nical designs can cope with this, like synchronisation

procedures or a linking database. Long term evolution

towards a integrated system is also possible. Those

aspects are less relevant to capture in a goal model.

Centralized Versus Decentralized Deployment.

Decentralisation can be decided for organisational or

political reasons (e.g. in a federal country) but will

keep a national authority ensuring consistency, e.g.

the global cadastre can be kept at the federal level

while tax can be perceived at regional or city level.

However, this can induce possible cooperation prob-

lems in the organisation, e.g. in Belgium, the cadas-

tral rent is not being systematically updated because

the federal level has no revenue out of it and this im-

pacts the funding of cities.

Fiscal (Tax-based) Versus Legal Background. The

former is easier to fund and update (only for market

value and on a yearly basis) while the later is more

complex and expensive because it needs to be accu-

rate and kept up-to-date on a daily basis.

General Boundaries Versus Fixed Boundaries. The

former relies on visible features of the ground while

the later uses exact and marked coordinates. This is

already captured by the parcel ontology.

5 DISCUSSION AND RELATED

WORK

A systems approach to land registration and cadastre

was developed by (Zevenbergen, 2004). This work

focuses on the technical, legal and organisational as-

pects, and their interrelation of such systems of land

registration. The work stresses the need to have a fully

integrated system view covering both land registra-

tion and cadastre. It covers not only the static dimen-

sions (as described in section 2) but also dynamic di-

mensions, with a focus on the important adjudication,

transfer and subdivision processes. However, it only

relies on informal process modelling and is also miss-

GISTAM 2017 - 3rd International Conference on Geographical Information Systems Theory, Applications and Management

248

ing the capture of all the rationales driving the system

design.

A UML model for cadastral system was proposed

by (Tuladhar, 2003). It shows how different UML dia-

grams can capture both structural and behavioural di-

mensions of the system. However UML models have

a total lack of goal perspective: the closest diagram

is the use case diagram which can only capture func-

tional requirements and performing actors.

A KAOS model was build for modelling the Bel-

gian cadastre in 2002 (Dechesne et al., 2002). The

goal was to support the development of an uniﬁed

cadastral database. The object part of the model was

not aligned with the still emerging standards but is

based on the same key notion of right between a per-

son and a real property. Those concepts are also de-

tailed using a rich inheritance hierarchy. The pro-

posed goal model ﬁrst details the “as-is” system fo-

cusing on the main missions like: maintaining the

cadastral map up-to-date, performing value estima-

tion, managing sales, etc. It reveals some duplicated

data which were addressed by an improved “to-be”

goal model used to drive the system evolution.

6 CONCLUSIONS

In this paper, we have shown how goal models can

provide useful enhancements to LA domain models

in order to provide a better understanding and reason-

ing capabilities on the design of such complex sys-

tems. We illustrated some key mechanisms to struc-

ture goals and variants and also to reason on them.

Our modelling is still being enhanced to reach bet-

ter completeness (e.g. for planning tasks), more de-

sign variants (e.g. adjudication strategies) and also

to introduce the missing operation level that can pro-

vide a stronger link with technical requirements and

give better control on how to evolve the deployed sys-

tems. Our ultimate goal is to be incorporate our re-

sults in future evolutions of LA domain models be-

cause this will deﬁnitely help in the process of setting

up or evolving a LA system. We are currently apply-

ing our framework to the co-analysis of LA systems in

the perspective of European convergence with an ini-

tial focus on the neighbouring countries of Belgium.

ACKNOWLEDGEMENTS

We thanks the Belgian ACED (Cadastre and Land

Registration ofﬁce) for sharing their case with us.

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