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National Geospatial Digital Archive Greg Janée. Greg Janée May 31, 20052 Outline Two preservation misadventures Digital preservation problems Genesis.

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Presentation on theme: "National Geospatial Digital Archive Greg Janée. Greg Janée May 31, 20052 Outline Two preservation misadventures Digital preservation problems Genesis."— Presentation transcript:

1 National Geospatial Digital Archive Greg Janée

2 Greg Janée May 31, Outline Two preservation misadventures Digital preservation problems Genesis of NGDA Project approach/philosophy What it will mean to be a data provider

3 Greg Janée May 31, Domesday Book— 1086

4 Greg Janée May 31, Domesday Book— 1986

5 Greg Janée May 31, 20055

6 6 Meanwhile, back at NASA –Viking probes go to Mars 1999 –USC neurobiologist Joseph Miller asks for data –tapes coded “in a format so old that the programmers who knew it had died” –works off of paper records

7 Greg Janée May 31, Preservation issues Physical –media –systems Contextual –format –semantics –authenticity Legal –copyright

8 Greg Janée May 31, Project genesis NDIIPP –Library of Congress, 2000 –$100M –http://www.digitalpreservation.gov/ NGDA –UCSB (MIL) & Stanford (Branner Library) –$2.6M, 3 years –archive geospatial data on a national scale –http://www.ngda.org/

9 Greg Janée May 31, 20059

10 10 Some philosophy Archival has to be cheap & easy –must be distributed –but reality is little incentive, no funding Archive definition: –offers access now & in the future –no mandatory services beyond simple access Policy separated from mechanism Archive includes data semantics –key differentiator from text, audio, video

11 Greg Janée May 31, Philosophy, cont. Curatorial, not archeological approach –assumption: content comes in discrete, self- contained chunks Preservation by format definition, archival & association –support for derivative forms, services Must support long-term preservation –need to migrate archive itself

12 Greg Janée May 31, MIT Media Lab Stewart Brand, “How Buildings Learn,” p. 53

13 Greg Janée May 31, MIT Building 20 Ibid., p. 26

14 Greg Janée May 31, system databasestorage handle resolver database Typical repository architecture database handle resolver database fragile

15 Greg Janée May 31, NGDA architecture storage subsystem standard, public data model archival system databases, caches, etc. bulk loader ingest ADLOAI Web access

16 Greg Janée May 31, Post-NGDA architecture storage subsystem standard, public data model Web

17 Greg Janée May 31, Storage system requirements Req’s: –associate UUIDs/RIDs with bitstreams –retrieve global/local bitstream by UUID/RID –determine (parent) UUID of any bitstream –list all UUIDs Satisfied by: –any filesystem –tag URIs for UUIDs tag:library.ucsb.edu,2005:identifier

18 Greg Janée May 31, Archival objects directory UUID component RID UUID

19 Greg Janée May 31, Example USGS DOQQ GeoTIFFFGDC Object x x.tiffx.fgdcx.gif metadata data derived TIFF subtypeOf

20 Greg Janée May 31, Object types Data, other content Format definitions Semantic definitions Providers Organizational structures –collection –series –ingest session

21 Greg Janée May 31, Archive-provider agreement Defines –common structure of objects to be ingested –necessary validations –associations to other objects assumes pre-loading of semantic definitions –policies, rights, etc. Represents choke point –requires human evaluation


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