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Diego Barros & Robson FidalgoICCSA 2010
An Architecture and a Metamodel for ProcessingAnalytic and Geographic Multilevel Queries
Diego Martins Vieira Barros1,2 & Robson do Nascimento Fidalgo1
1 - Center of Informatics - Federal University of Pernambuco (UFPE), Recife, Brazil
2 - São Francisco’s Hydroelectric Company (CHESF), Recife, Brazil
Diego Barros & Robson FidalgoICCSA 2010
Outline
• Introduction
– Motivation and Basic Concepts
• AGIS
– Basic Concepts, Architecture and Metamodel
• Case Study
• Related Work
• Conclusion
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Diego Barros & Robson FidalgoICCSA 2010
Introduction (Motivation)
• SOLAP tools are dependent on specific OLAP
languages and servers
• Queries for spatial analysis are typically large
and complex
– involve selections, projections, aggregations and joins
– the effort to write these queries manually is not a
trivial task for a non-specialist user
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Diego Barros & Robson FidalgoICCSA 2010
Introduction (Basic Concepts)
• OLAP– Multidimensional and multilevel processing
• Multidimensional: What is the total sales by product category, store name and year?”
• Multilevel: What is the total sales by product category, store name and year, semester, quarter, month and day?”
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Pro
du
ct
Store
Time
+Year+Semester+Quarter+Month +Day
Diego Barros & Robson FidalgoICCSA 2010
Introduction (Basic Concepts)
• OLAP– Analytic queries are typically large and complex for
non-specialist users (joins, group by, etc.)
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“What is the total sales by product category, store name and year?”
Diego Barros & Robson FidalgoICCSA 2010
• GIS
– Geographic processing
• Topological: Touches, Within, Crosses, Disjoint, Overlaps, etc.
• Metric: Area, Length, Distance, etc.
– Theme overlapping
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Source: www.vigeocities.com
Introduction (Basic Concepts)
Diego Barros & Robson FidalgoICCSA 2010
• GIS– Analytic and geographic queries are also typically
large and complex for non-specialist users (joins, group by, spatial operations, etc.)
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“What is the average sales by store for stores located in cities adjacent to Recife city?”
Introduction (Basic Concepts)
Diego Barros & Robson FidalgoICCSA 2010
• SOLAP
– Multidimensional/multilevel and geographic processing
– Dependent on specific OLAP languages and servers• There is no de jure standard language for OLAP yet, like
ISO/IEC SQL is to Relational DBMS or ISO/OGC SQL is to
Spatial DBMS
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Introduction (Basic Concepts)
Diego Barros & Robson FidalgoICCSA 2010
AGIS (Basic Concepts)
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• AGIS = Analytic and Geographic Information Service
• Provide a service for analytic and geographic multilevel processing that:
– Abstracts the complexity of writing these queries
– Uses consolidated and non-proprietary standards
Diego Barros & Robson FidalgoICCSA 2010
AGIS (Architecture)
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Diego Barros & Robson FidalgoICCSA 2010
AGIS (Architecture)
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- Component that corresponds to an application for requesting the service provided by the AGIS Engine- It can be a graphical interface implemented as a Web client , desktop or another application
Diego Barros & Robson FidalgoICCSA 2010
AGIS (Architecture)
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- Responsible for 1) generating queries for analytic and geographic multilevel processing 2) sending these queries to the SDBMS that executes them-Receives, through its programming interface, a set of query parameters sent form an AGIS Application and returns the query result to it.- Consists of two subcomponents
Diego Barros & Robson FidalgoICCSA 2010
AGIS (Architecture)
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-Component to access and provide AGIS metadata
Diego Barros & Robson FidalgoICCSA 2010
AGIS (Architecture)
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-Component that generates SQL queries with multilevel aggregations (GROUP BY clause) and geographic restrictions (spatial operators)
Diego Barros & Robson FidalgoICCSA 2010
AGIS (Architecture)
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- Component that corresponds to the XML repository of metadata, which defines the metadata needed to generate queries for analytic and geographic multilevel processing- Defines the metadata that describes how the geographic database must be organized to allow the generation of queries
Diego Barros & Robson FidalgoICCSA 2010
AGIS (Architecture)
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- Component that processes queries generated and submitted by AGIS Engine
Diego Barros & Robson FidalgoICCSA 2010
AGIS (Architecture)
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- Component that corresponds to the tables (schema and data) of AGIS architecture- It can be a transactional GDB or a Spatial Data Warehouse
Diego Barros & Robson FidalgoICCSA 2010
AGIS (Metamodel)
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Diego Barros & Robson FidalgoICCSA 2010
AGIS (Metamodel)
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- The root of the proposed metamodel
Diego Barros & Robson FidalgoICCSA 2010
AGIS (Metamodel)
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- Each feature type represents a geographic layer/theme that can be analyzed- Country, Region, State and City
Diego Barros & Robson FidalgoICCSA 2010
AGIS (Metamodel)
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- Each geographic hierarchy defines the position in which the feature types should be processed in an aggregation operation
- H1: Region→ State → City- H2: Country → State → City- H3: Region→ City- H4: State → City
Diego Barros & Robson FidalgoICCSA 2010
AGIS (Metamodel)
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- Each geographic level is associated with a feature type and represents the position of the feature type in the hierarchy
Diego Barros & Robson FidalgoICCSA 2010
AGIS (Metamodel)
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- Each measure represents a fact (measurable value that varies over time) to be analyzed
- Area- Rainfall
Diego Barros & Robson FidalgoICCSA 2010
AGIS (Metamodel)
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- Each geographic context corresponds to an analysis view- Denomination given to an analysis scope that corresponds to an abstract container
- C1: H1; Area and Rainfall
Diego Barros & Robson FidalgoICCSA 2010
AGIS (Metamodel)
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- Each filter corresponds to a set of fields from a table of the GDB that can be used as a selection/restriction criterion
- Vegetation type- Climate type
- Specialized in two types
*Only used on WHERE clause
Diego Barros & Robson FidalgoICCSA 2010
AGIS (Metamodel)
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- Corresponds to conventional restriction operations of SQL
- Vegetation type- Climate type
What is the average power produced by power stations built since 1995?
Diego Barros & Robson FidalgoICCSA 2010
AGIS (Metamodel)
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- Corresponds to conventional and/or spatial operations of SQL
- Vegetation type and its geometry- Climate geometry
What is the total power produced by power stations located in states that intersects the tropical wet climate?
Diego Barros & Robson FidalgoICCSA 2010
AGIS (Metamodel)
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- Occurs between a pair of columns of the tables to be joined- Conventional filter
-Defined from fields that are not on the same table that contains the measures
- Geographic level- Between two levels of a geographic hierarchy defined from normalized tables-Connect the table containing the geographic level with the lowest granularity and the table containing the measures
Diego Barros & Robson FidalgoICCSA 2010
AGIS (Metamodel)
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- Additional information about a particular theme/layer that can be returned in query results- Political party and name of the Mayor of a City feature type- Not part of geographic hierarchies- The same column can be defined as a filter and as a property
*Only used on SELECT clause
Diego Barros & Robson FidalgoICCSA 2010
AGIS (Metamodel)
• AGIS XML Schema
– Metamodel implementation
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…
Diego Barros & Robson FidalgoICCSA 2010
Case Study
• Proof of concept
– Analyze the electrical energy situation in Brazil, in
terms of generation and transmission
– Data from the Brazilian Agency of Electric Energy
– Simple Java client – AGIS WEB
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Diego Barros & Robson FidalgoICCSA 2010
Case Study
• Geographic Database - Brazilian Agency of Electric Energy
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Diego Barros & Robson FidalgoICCSA 2010
Case Study
• Metadata– Feature type
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Diego Barros & Robson FidalgoICCSA 2010
Case Study
• Metadata– Geographic hierarchy– Measure
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Diego Barros & Robson FidalgoICCSA 2010
Case Study
• Metadata– Conventional filter
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Diego Barros & Robson FidalgoICCSA 2010
Case Study
• Metadata– Spatial filter
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Diego Barros & Robson FidalgoICCSA 2010
Case Study
• Metadata– Geographic context
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Diego Barros & Robson FidalgoICCSA 2010
Case Study
• AGIS WEB graphical interface
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Diego Barros & Robson FidalgoICCSA 2010
Case Study
• Analytic and Geographic Multilevel Query
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Diego Barros & Robson FidalgoICCSA 2010
Related Work
• GOLAPA [1]
• GeoMondrian [12]
• JMap [13,14]
• GeWOlap [2]
• OLAP for ArcGIS [15]
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Diego Barros & Robson FidalgoICCSA 2010
Related Work
• As there is no de jure standard language for OLAP yet, these
works are dependent on specific OLAP languages and servers
• On the other hand, AGIS proposal aims to provide a service to
perform analytic and geographic multilevel processing without
dependence on an OLAP server
• AGIS should not be considered a SOLAP solution, because it is
a service that aims to enrich the set of functionalities of GIS
applications (AGIS is not based on an OLAP server)
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Diego Barros & Robson FidalgoICCSA 2010
Conclusion
• Contributions
– Definition of a three-tiered architecture (AGIS Architecture)
– Specification of AGIS Metamodel using UML and XML
– Possibility of performing analytic and geographic multilevel
queries, without needing to write manually these queries
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Diego Barros & Robson FidalgoICCSA 2010
Conclusion
• Future work
– Implementation of a geographic hierarchy among
spatial objects (i.e. using contains spatial relationship)
– Use of AGIS with huge databases
– Improve AGIS graphical interface
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Diego Barros & Robson FidalgoICCSA 2010
References
1. Fidalgo, R.N.: Uma Infra-estrutura para Integração de Modelos, Esquemas e Serviços
Multidimensionais e Geográficos. Doctorate Thesis, Federal University of Pernambuco,
Recife, PE (2005)
2. Bimonte, S., Tchounikine, A., Miquel, M.: Spatial OLAP: Open Issues and a Web Based
Prototype. In: 10th AGILE International Conference on Geographic Information Science, p.
11 (2007)
3. GeoMondrian Project, http://www.geo-mondrian.org
4. Kheops JMap, http://www.kheops-tech.com/en/jmap
5. Kheops JMap Spatial OLAP, http://www.kheops-tech.com/en/jmap/solap.jsp
6. ESRI OLAP for ArcGIS,
http://www.esri.com/software/arcgis/extensions/olap
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Diego Barros & Robson FidalgoICCSA 2010
An Architecture and a Metamodel for ProcessingAnalytic and Geographic Multilevel Queries
Diego Martins Vieira Barros1,2 & Robson do Nascimento Fidalgo1
1 - Center of Informatics - Federal University of Pernambuco (UFPE), Recife, Brazil
2 - São Francisco’s Hydroelectric Company (CHESF), Recife, Brazil