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OGC Geospatial Summit September 15, 2008

OGC Geospatial Summit September 15, 2008. CQL and SRU Ray Denenberg, Library of Congress OASIS Search Web Services Technical Committee. Brief History. Brief History. Late 90s, Pressure to make Z39.50…. Simpler, more comprehensible,more implementable. Brief History.

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OGC Geospatial Summit September 15, 2008

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  1. OGC Geospatial Summit September 15, 2008 CQL and SRU Ray Denenberg, Library of CongressOASIS Search Web Services Technical Committee

  2. Brief History

  3. Brief History • Late 90s, Pressure to make Z39.50…. • Simpler, more comprehensible,more implementable

  4. Brief History • Late 90s, Pressure to make Z39.50…. • Simpler, more comprehensible,more implementable • But most important: Web Compatible

  5. Brief History • Late 90s, Pressure to make Z39.50…. • Simpler, more comprehensible,more implementable • But most important: Web Compatible • …..while retaining the Z39.50 semantics and abstractions

  6. Roughly speaking …. • SRU/CQL is the XML/Web version of Z39.50.

  7. Roughly speaking …. • SRU/CQL is the XML/Web version of Z39.50.Where: • SRU corresponds to the Z39.50 protocol • CQL corresponds to the Z39.50 query

  8. Timeline • 1997-2001 A few false starts … • 2001 Work on SRU began • 2002 Version 1.0 • 2004 Version 1.1 • 2007 Version 1.2 • In progress Version 2.0, OASIS SWS TC

  9. An SRU Protocol Request http://www.loc.gov/sru?version=1.1&operation=searchRetrieve&query=dinosaur&maximumRecords=1 &recordSchema=dc

  10. Break it down: http://www.loc.gov/sru? version=1.1&operation=searchRetrieve& query=dinosaur &maximumRecords=1 &recordSchema=dc Server Parameters CQL Query More parameters

  11. query=dinosaur CQL Query

  12. CQL “Contextual Query Language”

  13. CQL’s Goals

  14. CQL’s Goals • Support simple queries with simplicity, Number one goal

  15. CQL’s Goals • Support simple queries with simplicity, • and complex expressions with exactly the complexity needed: no more, no less.

  16. Simple CQL Queries

  17. Simple CQL Queries • cat (simplest)

  18. Simple CQL Queries • cat (simplest) • cat and dog (simple boolean)

  19. Simple CQL Queries …… • cat (simplest) • cat and dog (simple boolean) • title = cat (index search)

  20. ….. A little more complex • cat • cat and dog • title = cat • dc.title = cat(index qualified)

  21. Qualified index • title = cat • dc.title = cat • bib.title = cat

  22. Qualified index • title = cat • dc.title = cat • bib.title = cat • geo.latitude = 22.6

  23. Qualified index • title = cat • dc.title = cat • bib.title = cat • geo.latitude = 22.6 • geo.bound encloses "45.3, 19.0"

  24. Relations <index> <relation> <search term>

  25. <index> <relation> <search term> Search Clause

  26. <index> <relation> <search term> Search Clause (e.g. title = cat)

  27. Cat • Title = cat Both are search clauses: in the first, the index and relation are defaulted.

  28. cat Same as • <default Index> <default relation>cat

  29. Some built-in relations … • <, >, <=, >=,<> • =the default relation, server defined • == Exact • adj Adjacency • Within • encloses

  30. RelationModifiers

  31. <index> <relation>/<modifier> <search term> Relation modifier Search Clause

  32. RelationModifiers • Stem • relevant • Fuzzy • Phonetic • partial

  33. Relation Modifier Example • Geo.city =/phonetic washintin Relation modifier

  34. Partial geo.area encloses/partial “washington DC"

  35. Proximity “Find cat and dog in the same sentence” cat prox//sentence dog

  36. Proximity cat prox//sentence dog same as: Cat prox/distance=0/unit=sentence/unordered dog

  37. Proximity prox/distance=0/unit=sentence/unordered

  38. geo.cityname = washington  prox/distance<=50/geo.unit=miles geo.cityname=baltimore Cities with name “washington” within 50 miles Of cities with name “baltimore”

  39. Proximity Exclusion (a 2.0 feature) Cities with name “washington” not within 50 miles Of cities with name “baltimore” geo.cityname = washington  prox/distance<=50/geo.unit=miles/not geo.cityname=baltimore

  40. Window Relation(a 2.0 feature) dc.title window/distance<5/unit=word "fries salt vinegar" fries, salt, and vinegar all within a span of 5 words

  41. geo.region Window /distance<200/geo.unit=miles/cityname “baltimore washington richmond" Regions containing cities with names Baltimore, Washington, and Richmond within a 200 mile area.

  42. Context sets

  43. Context sets • Indexes • Relations • Relation modifiers • Boolean Modifiers

  44. subject any/relevant "fish frog“ find records whose subject field includes words like shark, tuna, coelocanth, toad, amphibian, etc.  

  45. subject any/relevant "fish frog" Relation modifier index relation Subject to context qualification

  46. dc.subject any/relevant "fish frog" Context set

  47. dc.subject any/rel.lr "fish frog" A specific Relevance algorithn Context set

  48. geo.bounds within/partial/geo.nwse "43.772 -101.411 31.7723 -77.7499") and        (geo.keywords any "biologic ecologic"

  49. geo.bounds within/partial/geo.nwse "43.772 -101.411 31.7723 -77.7499") and        (geo.keywords any "biologic ecologic" Break that down…….

  50. geo.bounds within/partial/geo.nwse  "43.772 -101.411 31.7723 -77.7499" and        geo.keywords any "biologic ecologic"

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