MECOSIG Adapted to the Design of Distributed GIS

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Title: MECOSIG Adapted to the Design of Distributed GIS

1
MECOSIG Adapted to the Design of Distributed GIS

2
MECOSIG

A method devoted to GIS design and implementation
published in 1996 considering
GIS as an Information System (IS) where IS ?
Organization (systemic approach)
Organization as the core of the method
The method has been progressively improved (last
decade)
Emergence of distributed GIS involved
reassessment of the methodology
new concerns and tools (fitting the requirements
of distributed environments) identified

3
MECOSIG - Design protocol

Method covering the complete GISs lifecycle
using specific tools at different abstraction
levels
Descriptive to Logical-Physical level...
Design protocol is summarized into a monitoring
matrix
every cell relates to
specific tools (formalisms, models, prototyping
)
semantic concerns (metadata, documentation )
Main concerns are
Organization, Data, Data flows, Processes
MECOSIG suggested to go twice through the
monitoring matrix
analysis stage (not anymore taken into account
because of redundancy with the descriptive level
in conception step)
conception step

4
MECOSIG - Monitoring Matrix
5
Adaptations - Descriptive level

6
Adaptations - Descriptive level

Concerning processes (in particular crossed
processes in distributed GIS), interactions
between groups of actors and the System are
identified in terms of
textual descriptions
UML use cases
Data are identified according to use cases
Data are described in a catalogue and quality
must be analysed
Use of standards (ISO 19110 19115) is
recommended
Further agreements must be achieved in order to
incorporate semantic rules in spatial data domain
(interoperability requirements )

7
MECOSIG - Monitoring Matrix
8
Adaptations - Conceptual level

UML class diagram used to design Data (original
formalism proposed in MECOSIG - CONGOO is
substituted)
is internationally admitted as standard (System
modelling)
offers more than only one diagram
design can combine serial of models to depict a
context
Specificity of spatial data in UML
objects geometry
a lot of studies e.g. COMOSIG Workshops ER2004,
Bédard al., 2004 dealt with
stereotypes or tagged values allow to adapt UML
topological relationships
concept of topological matrix (originally from
CONGOO) is added and adapted
two kinds of topological matrix are available
the traditional matrix and the strong one

9
Adaptations - Conceptual level
10
Adaptations - Conceptual level

Every use case is extracted from the descriptive
level and detailed using UML activity diagrams
Sequence diagrams are used to conceptualize
specific scenarios of activity diagrams

11
MECOSIG - Monitoring Matrix
12
Adaptations - Organizational level

Facing the implementation of a distributed
infrastructure, important organisational
constraints must be met
missions of all actors should be assessed and
possibly redefined
new tasks are introduced in order to guarantee
maintenance, permanent working and growth of the
distributed System
new data flows are generated and others have to
be adapted
data exchange must be performed easily and in a
transparent way for all users
access to metadata ISO standards - particularly
metadata related to quality (data usability and
appraisal of final results)
some data / services access can be restricted or
subject to authorization(s)

13
Adaptations - Organizational level

From these purposes
coming up representatives committees in charge
of coordination tasks
formalization can also be introduced to depict
their tasks (UML use cases, activity sequence
diagrams, )

14
MECOSIG - Monitoring Matrix
15
Adaptations - Logical-Physical level

Roles and tasks of all actors should be clearly
specified
key is to associate all actors in the new System
which will be set up
e.g.
sensitizing and training sessions to facilitate
the understanding of the re-engineered system
possible reallocation of human resources
Constitution of the representatives committees
in charge of coordination tasks
competent and representative of the various
departments or organizations
receiving the ability to act decisively
Managerial economies and economies of scale could
be achieved
Acquisition of common reference data
Globalisation of software licenses

16
Adaptations - Logical-Physical level

A technical study must be completed
to guarantee the required degree of
interoperability
to identify precisely
add-on hardware and software
distributed system components
systems for cross-relating items of information
across multiple sources
Modelling process is to design objects which must
be deployed in a distributed System
e.g. data storage structure (components and
deployment UML diagrams)
previous activity and sequence diagrams
(conceptual level) are improved
by adding objects dealing with data flows,
procedures and processes according to GIS
software, tools and DBMS specificities...