The Vuel Concept: Towards The Vuel Concept: Towards a new way to manage a new way to manage

Multiple Representations in Multiple Representations in Spatial DatabasesSpatial Databases

ISPRS / ICA WorkshopMulti-Scale Representations of Spatial Data

OttawaJuly 7th, 2002

Eveline Bernier, M.Sc.Yvan Bédard, Ph.D.

Presentation OutlinePresentation Outline

The context : MOD and SOLAPThe context : MOD and SOLAP

The nature of the Multiple RepresentationsThe nature of the Multiple Representations

The Vuel concept The Vuel concept

The SOLAP prototypeThe SOLAP prototype

ConclusionConclusion

Map-On-DemandMap-On-Demand

Maps are created upon a set of constraints Maps are created upon a set of constraints

defined by the user.defined by the user.

The user can select the scale and the themes to The user can select the scale and the themes to

be displayed.be displayed.

On the web, the map must be displayed as fast On the web, the map must be displayed as fast

as possible (< 10 sec.).as possible (< 10 sec.).

Spatial On-Line Analytical Spatial On-Line Analytical Processing (SOLAP)Processing (SOLAP)

A visual platform built especially to support A visual platform built especially to support rapidrapid and and easyeasy spatio-temporal analysis and spatio-temporal analysis and exploration of data.exploration of data.

No query language. No query language.

Based on a multidimensional structure.Based on a multidimensional structure.

Operations such as drill-down, drill-up and drill-Operations such as drill-down, drill-up and drill-across.across.

SOLAP OperationSOLAP Operation

Drill-Down

Several Display ModesSeveral Display Modes

ProblematicProblematic There is a need, for both applications, to display

a same reality according to different points of view and differents abstraction levels.

On-the-Fly generalization

• not efficient enough to supports such applications

Existing MR structures • don’t support all kinds of

multiplicity (geometric, semantic and graphic)

• and are multi-scale only.

MultiplicitiesMultiplicities

Multi-Scale Single-ScaleG

eo

me

tric

Gra

ph

icS

em

an

tic

View B

View A

View C

View X

View Y

E

View XView YView A

View B

View ABuilding

View B

House

View X

View Y

Assessment Parcel

Cadastral Parcel

Proposed SolutionProposed Solution

To develop a new approach that extends multiple representation concepts for added flexibility in spatial databases.

This structure should support different geometric, semantic or graphic representations for the same element of the reality, according to different or similar granularities.

The VUELThe VUEL

an idea [Bédard et al., 2000]:

influenced by multidimensional data structures;

aimed at supporting spatial multidimensional applications (e.g. SOLAP).

(View Element)What it is:

the visible part of a view.

VUEL

Geometric

GraphicSemantic

a unique combinaison of semantic, geometric and graphic occurrence relations.

The VuelThe Vuel

Ground Reality

Building

View 4

VUEL 4

House

View 1

VUEL 1

House

Vie

w 2

VUEL 2

Building

View

3

VUEL 3

Geometric

GraphicSemantic

VUEL

The Vuel Conceptual ModelThe Vuel Conceptual Model

Built with UML and based on a multidimensional database paradigm.

The vuel is presented as a central table linking three dimensions:

• semantic, geometric, graphic.

A spatial database view (e.g. a map) becomes an aggregation of vuels.

Visual Basic

SOLAP Prototype

ImplementationImplementation

SOLAP InterfaceSOLAP Interface

DEMO

ConclusionConclusion

The conceptual model can be implemented on an existing relational plateform.

The VUEL concept is a flexible database view engine and represents a new solution to manage multiple representations because it supports simultaneously geometric multiplicity, semantic multiplicity and graphical multiplicity.

Supports different combinations of geometry, semantic and graphic semiology.

This structure allows a user to easily navigate between all the multiplicities, at the occurrence level as well as at the class level.

Future WorksFuture Works Continue the development of the SOLAP application based

on the vuel structure; Add new functionalities, temporal aspect, other display

modes, implementation on a «real» multidimensional structure, etc.

Develop a web-based system that supports maps-on demand;

SQL-Server (VUEL) – Geomedia WebMap – ASP.

Add generalization functionalities; Based on a pattern approach.

Thanks!

Questions??????