Examinando por Materia "GIS"
Mostrando1 - 7 de 7
Resultados por página
Opciones de clasificación
- Ponencia en CongresoAggregation languages for moving object and places of interest(2008) Gómez, Leticia Irene; Kuijpers, Bart; Vaisman, Alejandro Ariel"We address aggregate queries over GIS data and moving object data, where non-spatial information is stored in a data warehouse. We propose a formal data model and query language to express complex aggregate queries. Next, we study the compression of trajectory data, produced by moving objects, using the notions of stops and moves. We show that stops and moves are expressible in our query language and we consider a fragment of this language, consisting of regular expressions to talk about temporally ordered sequences of stops and moves. This fragment can be used not only for querying, but also for expressing data mining and pattern matching tasks over trajectory data."
- Artículo de Publicación PeriódicaAnalytical queries on semantic trajectories using graph databases(2019-10) Gómez, Leticia Irene; Kuijpers, Bart; Vaisman, Alejandro Ariel"This article studies the analysis of moving object data collected by location-aware devices, such as GPS, using graph databases. Such raw trajectories can be transformed into so-called semantic trajectories, which are sequences of stops that occur at “places of interest.” Trajectory data analysis can be enriched if spatial and non-spatial contextual data associated with the moving objects are taken into account, and aggregation of trajectory data can reveal hidden patterns within such data. When trajectory data are stored in relational databases, there is an “impedance mismatch” between the representation and storage models. Graphs in which the nodes and edges are annotated with properties are gaining increasing interest to model a variety of networks. Therefore, this article proposes the use of graph databases (Neo4j in this case) to represent and store trajectory data, which can thus be analyzed at different aggregation levels using graph query languages (Cypher, for Neo4j). Through a real-world public data case study, the article shows that trajectory queries are expressed more naturally on the graph-based representation than over the relational alternative, and perform better in many typical cases."
- Tesis de doctoradoCategorical sequential pattern mining in a spatio-temporal environment(c2009) Gómez, Leticia Irene; Vaisman, Alejandro Ariel"En esta tesis argumentamos que la información de trayectorias también puede ser integrada con datos GIS y OLAP, generando un marco poderoso de análisis".
- Trabajo final de especializaciónInventario vial georreferenciado(2020) Arequipa, Patricia Noemí; Aizemberg, Diego ArielEl presente trabajo tiene como objetivo general "generar un algoritmo práctico que permita vincular y ajustar lo mejor posible los puntos de inventario a puntos georreferenciados, obteniendo así las coordenadas geográficas de cada punto que describe a las rutas, esto permitirá mapear el inventario vial y compartir el mismo de manera oficial."
- Artículo de Publicación PeriódicaMapping spatiotemporal data to RDF: a SPARQL endpoint for Brussels(2019) Vaisman, Alejandro Ariel; Chentout, Kevin"This paper describes how a platform for publishing and querying linked open data for the Brussels Capital region in Belgium is built. Data are provided as relational tables or XML documents and are mapped into the RDF data model using R2RML, a standard language that allows defining customized mappings from relational databases to RDF datasets. In this work, data are spatiotemporal in nature; therefore, R2RML must be adapted to allow producing spatiotemporal Linked Open Data.Data generated in this way are used to populate a SPARQL endpoint, where queries are submitted and the result can be displayed on a map. This endpoint is implemented using Strabon, a spatiotemporal RDF triple store built by extending the RDF store Sesame. The first part of the paper describes how R2RML is adapted to allow producing spatial RDF data and to support XML data sources. These techniques are then used to map data about cultural events and public transport in Brussels into RDF. Spatial data are stored in the form of stRDF triples, the format required by Strabon. In addition, the endpoint is enriched with external data obtained from the Linked Open Data Cloud, from sites like DBpedia, Geonames, and LinkedGeoData, to provide context for analysis. The second part of the paper shows, through a comprehensive set of the spatial extension to SPARQL (stSPARQL) queries, how the endpoint can be exploited."
- Artículo de Publicación PeriódicaPiet: a GIS-OLAP implementation(2007) Vaisman, Alejandro Ariel; Gómez, Leticia Irene; Kuijpers, Bart; Escribano, Ariel"Data aggregation in Geographic Information Systems (GIS) is a desirable feature, although only marginally present in commercial systems, which also fail to provide integration between GIS and OLAP (On Line Analytical Processing). With this in mind, we have developed Piet, a system that makes use of a novel query processing technique: first, a process called sub-polygonization decomposes each thematic layer in a GIS, into open convex polygons; then, another process computes and stores in a database the overlay of those layers for later use by a query processor. We describe the implementation of Piet, and provide experimental evidence that overlay precomputation can outperform GIS systems that employ indexing schemes based on R-trees."
- Ponencia en CongresoTemporal SOLAP: query language, implementation, and a use case(2012) Bisceglia, Pablo; Gómez, Leticia Irene; Vaisman, Alejandro Ariel"The integration of Geographic Information Systems (GIS) and On-Line Analytical Processing (OLAP), denoted SOLAP, is aimed at exploring and analyzing spatial data. In real-world SOLAP applications, spatial and non-spatial data are subject to changes. In this paper we present a temporal query language for SOLAP, called TPiet-QL, supporting so-called discrete changes (for example, in land use or cadastral applications there are situations where parcels are merged or split). TPiet-QL allows expressing integrated GIS-OLAP queries in an scenario where spatial objects change across time. We also present a prototype implementation, and show how this application is used in a real-world scenario: the analysis of protected areas in Uruguay."