Optimal point location in a monotone subdivision
SIAM Journal on Computing
Towards a theory of spatial database queries (extended abstract)
PODS '94 Proceedings of the thirteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Implementing data cubes efficiently
SIGMOD '96 Proceedings of the 1996 ACM SIGMOD international conference on Management of data
Towards tractable algebras for bags
Journal of Computer and System Sciences
Topological queries in spatial databases
PODS '96 Proceedings of the fifteenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Equivalence of Relational Algebra and Relational Calculus Query Languages Having Aggregate Functions
Journal of the ACM (JACM)
R-trees: a dynamic index structure for spatial searching
SIGMOD '84 Proceedings of the 1984 ACM SIGMOD international conference on Management of data
Object-Based Selective Materialization for Efficient Implementation of Spatial Data Cubes
IEEE Transactions on Knowledge and Data Engineering
Generalized Search Trees for Database Systems
VLDB '95 Proceedings of the 21th International Conference on Very Large Data Bases
Selective Materialization: An Efficient Method for Spatial Data Cube Construction
PAKDD '98 Proceedings of the Second Pacific-Asia Conference on Research and Development in Knowledge Discovery and Data Mining
Summarizability in OLAP and Statistical Data Bases
SSDBM '97 Proceedings of the Ninth International Conference on Scientific and Statistical Database Management
Efficient OLAP Operations in Spatial Data Warehouses
SSTD '01 Proceedings of the 7th International Symposium on Advances in Spatial and Temporal Databases
Pre-aggregation in Spatial Data Warehouses
SSTD '01 Proceedings of the 7th International Symposium on Advances in Spatial and Temporal Databases
Querying Multidimensional Databases
DBLP-6 Proceedings of the 6th International Workshop on Database Programming Languages
Maintaining Data Cubes under Dimension Updates
ICDE '99 Proceedings of the 15th International Conference on Data Engineering
Indexing Spatio-Temporal Data Warehouses
ICDE '02 Proceedings of the 18th International Conference on Data Engineering
Spatial hierarchy and OLAP-favored search in spatial data warehouse
DOLAP '03 Proceedings of the 6th ACM international workshop on Data warehousing and OLAP
Multidimensional data modeling for location-based services
The VLDB Journal — The International Journal on Very Large Data Bases
GIS: A Computing Perspective, 2nd Edition
GIS: A Computing Perspective, 2nd Edition
Representing spatiality in a conceptual multidimensional model
Proceedings of the 12th annual ACM international workshop on Geographic information systems
Time-dependent affine triangulation of spatio-temporal data
Proceedings of the 12th annual ACM international workshop on Geographic information systems
Spatiotemporal Aggregate Computation: A Survey
IEEE Transactions on Knowledge and Data Engineering
Data Mining: Concepts and Techniques
Data Mining: Concepts and Techniques
Towards a spatial multidimensional model
Proceedings of the 8th ACM international workshop on Data warehousing and OLAP
An open source and web based framework for geographic and multidimensional processing
Proceedings of the 2006 ACM symposium on Applied computing
Equivalence of queries combining set and bag-set semantics
Proceedings of the twenty-fifth ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems
Piet: a GIS-OLAP implementation
Proceedings of the ACM tenth international workshop on Data warehousing and OLAP
Computational Geometry: Algorithms and Applications
Computational Geometry: Algorithms and Applications
Data Mining With Ontologies: Implementations, Findings and Frameworks
Data Mining With Ontologies: Implementations, Findings and Frameworks
On the requirements for user-centric spatial data warehousing and SOLAP
DASFAA'11 Proceedings of the 16th international conference on Database systems for advanced applications
High-performance online spatial and temporal aggregations on multi-core CPUs and many-core GPUs
Proceedings of the fifteenth international workshop on Data warehousing and OLAP
Detecting summarizability in OLAP
Data & Knowledge Engineering
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Data aggregation in Geographic Information Systems (GIS) is a desirable feature, only marginally present in commercial systems nowadays, mostly through ad hoc solutions. We address this problem introducing a formal model that integrates, in a natural way, geographic data and non-spatial information contained in a data warehouse external to the GIS. This approach allows both aggregation of geometric components and aggregation of measures associated to those components, defined in GIS fact tables. We define the notion of geometric aggregation, a general framework for aggregate queries in a GIS setting. Although general enough to express a wide range of (aggregate) queries, some of these queries can be hard to compute in a real-world GIS environment because they involve computing an integral over a certain area. Thus, we identify the class of summable queries, which can be efficiently evaluated replacing this integral with a sum of functions of geometric objects. Integration of GIS and OLAP (On Line Analytical Processing) is supported also through a language, GISOLAP-QL. We present an implementation, denoted Piet, which supports four kinds of queries: standard GIS, standard OLAP, geometric aggregation (like ''total population in states with more than three airports''), and integrated GIS-OLAP queries (''total sales by product in cities crossed by a river'', also allowing navigation of the results). Further, Piet implements a novel query processing technique: first, a process called subpolygonization decomposes each thematic layer in a GIS, into open convex polygons; then, another process (the overlay precomputation) computes and stores in a database the overlay of those layers for later use by a query processor. Experimental evaluation showed that for a wide class of geometric queries, overlay precomputation outperforms R-tree-based techniques, suggesting that it can be an alternative for GIS query processing.