Ogc geospatial Summit September 15, 2008 Brief History

OGC Geospatial Summit September 15, 2008  

Brief History

Brief History

• Late 90s, Pressure to make Z39.50….

• Simpler, more comprehensible,more implementable

Brief History

• Late 90s, Pressure to make Z39.50….

• Simpler, more comprehensible,more implementable
• But most important: Web Compatible

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

Roughly speaking ….

• SRU/CQL is the XML/Web version of Z39.50.

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

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

CQL

CQL’s Goals

CQL’s Goals

• Support simple queries with simplicity,

CQL’s Goals

• Support simple queries with simplicity,
• and complex expressions with exactly the complexity needed: no more, no less.

Simple CQL Queries

Simple CQL Queries

• cat (simplest)

Simple CQL Queries

• cat (simplest)

• cat and dog (simple boolean)

Simple CQL Queries ……

• cat (simplest)

• cat and dog (simple boolean)

• title = cat (index search)

….. A little more complex

• cat

• cat and dog

• title = cat

• dc.title = cat (index qualified)

Qualified index

• title = cat

• dc.title = cat

• bib.title = cat

Qualified index

• title = cat

• dc.title = cat

• bib.title = cat

• geo.latitude = 22.6

Qualified index

• title = cat

• dc.title = cat

• bib.title = cat

• geo.latitude = 22.6

• geo.bound encloses "45.3, 19.0"

Relations

Cat

• Cat

• Title = cat

• Both are search clauses: in the first, the index and relation are defaulted.

cat

• cat

• Same as

• cat

Some built-in relations …

• <, >, <=, >=, <>

• = the default relation, server defined

• == Exact

• adj Adjacency

• Within

• encloses

Relation Modifiers

Relation Modifiers

• Stem

• relevant

• Fuzzy

• Phonetic

• partial

Relation Modifier Example

• Geo.city =/phonetic washintin

Partial

• geo.area encloses/partial “washington DC"

Proximity

• “Find cat and dog in the same

• sentence”

• cat prox//sentence dog

Proximity

• cat prox//sentence dog

• same as:

• Cat

• prox/distance=0/unit=sentence/unordered

• dog

Proximity

• prox/distance=0/unit=sentence/unordered

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

geo.region Window

• 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.

Context sets

Context sets

• Indexes

• Relations

• Relation modifiers

• Boolean Modifiers

SRU – Search/Retrieve via URL

SRU – Search/Retrieve via URL Features

• Result sets

SRU – Search/Retrieve via URL Features

• Result sets

• Result set refinement
• Request specific records
• Sorting

Result sets

• Result sets

• Retrieval

Result sets

• Result sets

• Retrieval

• Ability to request records in a particular XML schema, e.g.
• MODS
• DC
• GML

Result sets

• Result sets

• Retrieval

• Application Specific Diagnostics

Oasis SWS TC – Phase 1

• Abstract Protocol Definition

• From which bindings are derived.

• Bindings

• SRU 1.2 specification (+CQL 1.2)
• Opensearch

Phase 2

• SRU/CQL 2.0

• Description Language