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					Keeping remote datasets up to date
A standards based method for exchanging (geo-)data mutations
Keeping remote datasets up to date
A standards based method for exchanging (geo-)data mutations



•   Research plan
•   OpenGIS solution
•   Geo-solution?
•   History in information models
•   Conclusions
•   Further work
Predefined plan


Research Questions
• How can we distribute spatial data (in the context of
  Spatial Data Infrastructures) efficiently?
• Are there existing models that can be used for
  incremental updates.
• Are current standards in the spatial domain sufficient
  to implement an SDI with incremental updates, and if
  not what is missing.
Predefined plan


Possible scenarios
• Real time update: Every time the source dataset
  changes an update is pushed.
• Update on demand.
• Monthly updates.
Additional research questions


•   Why is the exchange of change-only geo data necessary?
•   What information and what mutations are already exchanged at
    the moment that (could) fall under the scope of the research
    and how is the exchange handled?
•   What kind of mutations have to be supported and what
    information about them has to be available?
•   What possibilities exist already within GML for the exchange of
    mutations?
•   What possibilities do other OpenGIS standards give for the
    exchange of mutations?
•   What standards or generally applied methods exist for the
    exchange of mutations outside the OpenGIS standards?
OpenGIS solution


Transactional - Web Feature Service (WFS-T)
• Supports insert, delete, update operations
• Accepted and used standard in GIS
• Already implemented (e.g. Geoserver)
• Provides standard interface to geo-databases (e.g.
  Postgresql/PostGIS, Oracle)
OpenGIS solution
                           Setup for mutation exchange based on WFS-T
                                                                        SOAP Request

  Application server                     INTERNET                                      Soap client
  Mutation server                                                                      Mutation client

                            SOAP
                          Response




                                                                                          WFS-T
            WFS


                                                                                         or
                                                                                                Intermedia
                                                                                                     ry
                                                                                                 Database

            Providers
          Main Database                                                                 Customers
           (versioned)                                                                 Main Database

           Provider                                                                     Customer


                                 Not yet available, must be developed
A Geo-solution ???


• Except for the geometry, what is special about geo-
  data mutations?
• Integration of GIS in enterprise/government IT
  (SOA, ESB, OSB)
• How do the OGC interface specs fit the “mainstream”
  IT standards?



At what level do we fit the mutation semantics?
History in current information models


NEN3610

 NEN3610 Timestamp Meaning
  featureStartTime   System time at which the geographic feature was created.

  featureEndTime     System time after which the geographic feature is invalid.

  versionStartTime   System time at which this version of the geographic feature becomes valid.

  versionEndTime     System time after which this version of the geographic feature is invalid.

  startTime          Creation date of the geographic feature in the real world.

  endTime            Date on which the geographic feature ceases to exist in the real world.
History in current information models


TOP10NL
• objectBeginTime
• objectEndTime
• versionStartTime
• versionEndTime

TOP10NL does not use the real world start and end times
History in current information models

IMKAD




  Geometry        Administrative
History in current information models
BAG
•validFrom
•validThrough
•AuditTrail
     •createdOn
     •ChangedOn
                                                                   TITEL
•SourceDocument                                                                    Class Diagram: historie en leggen van relaties
     •Date
                      BagObject
-identificatie : String                                                    BagObjectVersie                                   AuditTrail
+afvoeren()                                        -heeft
                                                                -geldigVan : Date                                     -aangemaaktOp : Date
+aanmelden() : BagObjectVersie                                  -geldigTot : Date                     1               -aangemaaktDoor : String
+wijzigen(in bagObjectVersion : BagObjectVersie)   -bagObject   -officieel : boolean                                  -gewijzigdOp : Date
                                                    1
+ophalen()                                                      -inOnderzoek : boolean                           1    -gewijzigdDoor : String
+createNewVersion()
+find() : List                                              *                                         1

                                                                                                                          BronDocument
                                                                                                                      -nummer : String
                                                                                                                 1    -datum : Date
History in current information models


RSGB is the
Referentiemodel for Stelsel Gemeentelijke Basisgegevens

A combination of the national system of Basisregistraties with
additional data for the specific work processes of the municipal
organization.

• When did something really happen or is it stated to have
happened? This describes when the recorded information is valid.
This is the reality timeline.
• When did the government know of the information? This is the
administrative timeline.
Conclusions


• Two methods for history registration:
   • object(versions) with begin time and end time
   • changes represented by (legal) documents.

• NEN3610 is nice, but not used effectively

• Mutation management is not a geo-problem
  don’t make a geo-solution
And now…


• Create general applicable solution for updates (try with
  cadastral data)
• Model history management in UML, derive required
  queries (is this possible?)
• Subscriptions = stored request for frequent updates
  (may be push technology)

				
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posted:5/8/2013
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