Searching the World Wide Web

Transcription

1 A Spatial Dimension for Searching the World Wide Web M. Andrea Rodríguez T. Centro de Investigación de la Web - CIW Universidad de Concepción andrea@udec.cl December -2002

2 Outline Search based on spatial operators Reasoning about spatial relations Modeling the geographic space in the Web Mapping Web documents onto a Geographic Map The Geographic Map as Topic Map in the Web Conclusions and future work

3 Diversity in Type of Information Text Images Video Audio

4 Diversity in Type of Information Text Images Video Audio

5 Diversity in Information Content Topic Text Time Geographic reference Etc

6 Diversity in Information Content Topic Text Time Geographic reference Etc

7 Queries based on spatial operators Retrieve hotels in Pucón or adjacent towns Retrieve ski resorts located within 100 Km from Santiago Retrieve airports and harbors in Chile that are within 100 km from each other

8 Retrieve hotels in Pucón and adjacent towns Keyword: Hotel and (Pucón or Villarrica or Caburga or.)

9 Retrieve hotels in Pucón and adjacent towns Keyword: Hotel and (Pucón or Villarrica or Caburga or.) Query: Select d.url From Document d SUCH THAT d MENTIONS hotels Where (d.g_reference IN Pucón or d.g_reference EQUAL Pucón or d.g_reference ADJACENT Pucón )

10 Retrieve ski resorts located within 100 kms from Santiago Keyword: Ski resorts and (Santiago or Rancagua or..)

11 Retrieve ski resorts located within 100 kms from Santiago Keyword: Ski resorts and (Santiago or Rancagua or..) Query: Select d.url From Document d SUCH THAT d MENTIONS ski resort Where Distance(d.G_reference, Santiago ) 100

12 Retrieve airports and harbors in Chile that are within 100 kms from each other Query: Select d1.url, d2.url From Document d1 SUCH THAT d1 MENTIONS airport, Document d2 SUCH THAT d2 MENTIONS harbor, Where Distance(d1.G_reference, d2.g_reference) 100 and (d1.g_reference IN Chile ) and (d2.g_reference IN Chile )

13 Seacrch System Arquitecture Search Engines Internet Web Servers SQuery Engine Query Parser System Utility Geographic Map

14 Reasoning about Spatial Relations Spatial relations define constraints in structural queries They are usually not stored in the database Their derivation and manipulation lay in the area of spatial reasoning

15 È Î È f f ÿf f f ÿf Î ÿf ÿf ÿf ÿf ÿf ÿf f ÿf ÿf f f ÿf È Î f f ÿf f ÿf ÿf ÿf ÿf ÿf È Î ÿf ÿf ÿf f f ÿf f f ÿf Topology È Î ÿf ÿf ÿf ÿf ÿf ÿf ÿf ÿf ÿf inside contains meets È Î ÿf f f f ÿf f f f ÿf disjoint inside contains meets disjoint

16 Orientation N NW W SW S SE E NE N NW W SW S SE S NE NW N NE W E SW S SE

17 Level Modeling Regions and Spatial Relations

18 Modeling Regions and Spatial Relations 0* PLACE 0* MBR: ((xu,yu),(xl,yl)) 0* 0* 0* inside south west 1 ("r 1 r 2 )inside(r 1,r 2 ) contains(r 2,r 1 ) ("r 1 r 2 )meet(r 1,r 2 ) ($x 1, x 2 )(meet( x 1, x 2 ) Ÿ inside(x 1, r 1 ) Ÿ inside(x 2, r 2 ))

19 A Geographic Map of Chile Chile Tarapaca Antofagasta Atacama Coquimbo Valparaiso Santiago O Higgins Maule BioBio Araucania Los Lagos Aisén Pucón Magallanes

20 Mapping Web Documents onto the Geographic Map Metadata-based mapping (ISO/TC 211) <spatrepinfo> <geodec> Name </geodesc> <geobox> </geobox> </spatrepinfo> <GeoBndBox> </GeoBndBox> <westbl> </westbl> <eastbl> </eastbl> <northbl> </northbl> <southbl> </southbl>

21 Mapping Web Documents onto the Geographic Map Keyword-based mapping Ocurrence and co-ocurrence of toponomies Ocurrence within the geographic hierarchy Co-ocurrence of toponimies and geographic entities

22 Geographic Map as Topic Map Topic Maps model the content of Web documents independently of Web ocurrences It exists as an standard ISO/IEC 13250:1999 Basic components: Topics and types of topics Associations and types of associations Ocurrences

23 Geographic Map as Topic Map <topic id="chiletm-topic"> <subjectidentity> <subjectindicatorref xlink:href="#chiletm"/> </subjectidentity> <basename> <basenamestring>chilean Map</baseNameString> </basename> </topic> <association> <instanceof><topicref xlink:href="ontopsi.xtmm#superclass-subclass"/></instanceof> <scope><topicref xlink:href="ontopsi.xtmm#ontology"/></scope> <member> <rolespec><topicref xlink:href="ontopsi.xtmm#superclass"/></rolespec> <topicref xlink:href="#place"/> </member> <member> <rolespec><topicref xlink:href="ontopsi.xtmm#subclass"/></rolespec> <topicref xlink:href="#country"/> </member> </association>

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25 Conclusiones and Future Work Queries based on spatial operations from textual informacion Extensions of current spatial query languages Indexing and seach algorithms Spatial and Semantic Constraints