Title: Preservation Issues Related to Digital Geospatial Data Steven P. Morris Head of Digital Library Initiatives North Carolina State University Libraries
1Preservation Issues Related to Digital Geospatial
Data Steven P. MorrisHead of Digital Library
InitiativesNorth Carolina State University
Libraries
Library of Congress Workshop
April 21, 2008
2Overview of the Problem Area Outline
- Revisiting Key Geospatial Data Types
- Risks to Digital Geospatial Data
- Value in Temporal/Historical Data
- Archiving Challenges
3Brief (Very) Overview of the Geospatial Domain
4Data Types Digital Orthophotography
- All 100 NC counties with orthos
- 1-5 flight years per county
- 30-300 gb per flight
5Geospatial Data Types Vector GIS
- County, municipal, state
- Detailed, accurate, current
- Frequently updated
- Cadastral (tax parcels)
- Street centerlines
- Zoning
- Topographic contours
- School, sheriff, fire
- Voting precincts
- More
6Data Types Spatial Databases
- Vector and raster data
- Relationships
- Behaviors
- Annotation
- Data Models
7Geospatial Data Types Cartographic
- GIS Software
- Software project file (.mxd, .apr, )
- Data layer file (.avl, .lyr, )
- PDF map exports
- Web Services-based representations
8Other Geospatial Data Types Place-based Data
Oblique Imagery
- Mobile, LBS, and, social networking applications
- Long-term cultural heritage value in non-overhead
imagery more descriptive of place and
function
Street View Images
Tax Dept. Photos
Road Videologs
9Geospatial Data Compelling Issues
- Dynamic content
- Constantly updated information
- Data versioning
- Digital object complexity
- Spatially enabled databases
- Complicated, multi-component formats
- Proprietary formats
10Risks to Geospatial Data
11How would you describe your current geospatial
archive?
12Digital Preservation Points of Failure
- Data is not saved, or
- cant be found, or
- media is obsolete, or
- media is corrupt, or
- format is obsolete, or
- file is corrupt, or
- meaning is lost
Solutions Migration Emulation Encapsulation XML
13Risks to Geospatial Data
- Producer focus on current data
- Data overwrite as common practice
- Future support of data formats in question
- No open, supported format for vector data
- Shift to web services-based access
- Data becoming more ephemeral
- Inadequate or nonexistent metadata
- Impedes discovery and use
- Increasing use of spatial databases for data
management - The whole is greater than the sum of the parts
14Value in Older Geospatial Data
15Value in Older Data Cultural Heritage
Future uses of data are difficult to anticipate
(as with Sanborn Maps)
16Value in Older Data Solving Business Problems
Land use change analysis
Site location analysis
Real estate trends analysis
Disaster response
Resolution of legal challenges
Impervious surface maps
Suburban Development 1993/2002 Near
Mecklenburg-Cabarrus County border
17Problem Flood and Hurricane Preparedness
18Application Impervious Surface Change Mapping
A.
B.
2002 Impervious
2004 Aerial Photography
C.
D.
2004 Impervious Update
2004 Impervious using 2002 Mask
19Problem Beach Erosion and Shoreline Change
20Application Shoreline Change Mapping
21Problem Tracking Land Use Change
22Application Land Use Change Mapping
Input Data
Output GIS Data
Using Mecklenburg County 2002 true color
orthorectified aerial photography
23(No Transcript)
24Preservation Challenges
25Challenge Vector Data Formats
- No widely-supported, open vector formats for
geospatial data - Spatial Data Transfer Standard (SDTS) not widely
supported - Geography Markup Language (GML) diversity of
application schemas and profiles a challenge for
permanent access - Spatial Databases
- The whole is more than the sum of the parts, and
the whole is very difficult to preserve - Can export individual data layers for curation,
but relationships and context are lost - Some thinking of using the spatial database as
the primary archival platform
26Challenge Preserving Geodatabases
- Spatial databases in general vs. ESRI Geodatabase
format - Not just data layers and attributesalso
topology, annotation, relationships, behaviors - ESRI Geodatabase archival issues
- XML Export, Geodatabase History, File
Geodatabase, Geodatabase Replication - Some looking to Geodatabase as archival platform
(in addition to feature class export)
27Challenge Cartographic Representation
Counterpart to the map is not just the dataset
but also models, symbolization, classification,
annotation, etc.
28Challenge Geospatial Web Services
- How to capture records from decision-
- making processes?
29Challenge Preservation Metadata
Results from a 2006 survey of all 100 NC counties
and 25 largest NC municipalities
30Challenge Data Capture
2006 Frequency of Capture Survey targeting North
Carolina counties and municipalities
Response yes 65.3, no 34.7 (out of
57.6 response rate)
31Challenge Digital Object Complexity
32Building Data Bundles The Zip Codes Example
33Where is the Dataset?
34Heres One!
- Files
- Multi-file dataset
- Georeferencing
- Metadata file
- Symbolization file
- Additional
- documentation
- License
- Disclaimer
- More
- Metadata
- FGDC
- Acquisition metadata
- Transfer metadata
- Ingest metadata
- Archive rights
- Archive processes
- Collection metadata
- Series metadata
35Other Challenges
- Rights management
- Data versioning
- Semantic issues
- Large scale content transfer
- Integrating older analog data
- More
36Looking for Solutions Outline
- Approaches to Archiving and Preservation
- Current and Recent Geoarchiving Projects
- Content Identification
- Content Selection
- Content Exchange
- Digital Repository Development
- Engaging Spatial Data Infrastructure
- Archives Processes
37Different Ways to Approach Preservation
- Technical solutions How do we preserve acquired
content over the long term? - Cultural/Organizational solutions How do we make
the data more preservableand more prone to be
preservedfrom point of production?
Current use and data sharing requirements not
archiving needs are most likely to drive
improved preservability of content and
improvement of metadata
38Different Ways to Approach Preservation
- Technical solutions How do we archive acquired
content over the long term? - Build data repositories not just as an end in
itself but also as a catalyst for discussion
within the data community - Develop repository ingest workflows create
technical points of engagement with other NDIIPP
preservation projects and build on collective
learning experience
39Different Ways to Approach Preservation
- Cultural/Organizational solutions How do we make
the data more preservableand more prone to be
archivedfrom point of production? - Engage data producer community and spatial data
infrastructure through outreach and engagement
influence practice - Sell the problem to software vendors and
standards development - Find overlap with more compelling business
problems disaster preparedness, business
continuity, road building, etc. - Start a discussion about roles at the local,
state, and federal level
40Current or Recent Geospatial Data Archiving
Projects
41Selected Geospatial Data Archive Projects
Project Organizations Funding
Persistent Archives Testbed San Diego Supercomputer Center, NARA NARA
VanMap San Diego Supercomputer Center Inter- PARES
Geospatial Repository for Academic Deposit Extraction EDINA JISC
Geospatial Electronic Records CIESIN NHPRC
various Carleton University various
National Geospatial Digital Archive UC Santa Barbara NDIIPP
Maine GeoArchives State of Maine NHPRC
42NC Geospatial Data Archiving Project
- Partnership between university library (NCSU) and
state agency (NCCGIA), with Library of Congress
under the National Digital Information
Infrastructure and Preservation Program (NDIIPP) - One of 8 initial NDIIPP collection building
partnerships - Focus on state and local geospatial content in
North Carolina (state demonstration) - Tied to NC OneMap initiative, which provides for
seamless access to data, metadata, and
inventories - Objective engage existing state/federal
geospatial data infrastructures in preservation
Serve as catalyst for discussion within industry
43NCGDAP Goals
- Repository Goal
- Capture at-risk data
- Explore technical and organizational challenges
- Project End Goal
- Data Producers Improved temporal data management
practices - Archives More efficient means of acquiring and
preserving data - Progress towards best practices
Temporal data management vs. long-term
preservation
44Content Identification
45Formal Inventory Processes
- Alleviate contact fatigue on part of local
agencies - 20 different NC state agencies contact local
agencies for data also, federal/regional
agencies - Geospatial data is complex, requiring lengthy
inventory process - Must capture descriptive, technical, and
administrative information related to the data - Make the inventory available as a sharable data
store
46What do Inventories Offer to Archives?
- Data Availability Information
- Detailed information by data layer
- Contact Information
- Minimal Metadata
- Descriptive, technical, administrative
- Rights Information
- Document Technical Environment
- Software used, formats, transfer methods
- Future Data Development Plans
47Detailed Information About Data
Source NC OneMap Data Inventory 2004
48Inventories as Source of MetadataExample
Surface Water
49Content Selection
50Selection Issues
- Most content is already at some level of risk
- Early-Middle-Late Stage issues
- Middle stage is usually the sweet spot, e.g.
TIFF orthophotos vs. raw images or compressed
images - Also added-value products digital maps,
cartographic representation - Digital maps record or not?
- Frequency of capture
51Problem Multiple choice for format type,
coordinate system, tiling scheme
52Time series vector data Parcel Boundary Changes
2001-2004, North Raleigh, NC
Continuously updated data Frequency of
snapshots? Different for various framework
layers?
53Sept. 2006 Frequency of Capture Survey
- Survey objective
- Document current practices for obtaining archival
snapshots of county/municipal geospatial vector
data layers - Seek guidance about frequency of capture
- Survey topics
- General questions about data archiving practice
- Specific questions about parcels, street
centerlines, jurisdictional boundaries, and
zoning - Survey subjects
- All 100 counties and 25 municipalities
- 58 response rate
- Survey conducted September 2006
54Data Capture Survey Results Overview
- Two-thirds of responding agencies create and
retain periodic snapshots - Long-term retention more common in counties with
larger populations - Storage environments vary, with servers and
CD-ROMs most common - Offsite storage (or both onsite and offsite) is
used by nearly half of the respondents - Popularity of historic images has resulted in
scanning and geo-referencing of hardcopy aerial
photos among one-third of the respondents
55Survey Observations
- Process of survey formulation and implementation
helped to socialize the problem of archiving data - Local innovation needs to be mined further to
inform development of best practices - Business drivers for archiving need more study
(e.g., stated adherence to retention policy) - Exposure to peer practice encourages archiving
- Pronounced local interest in scanning/rectifying
older analog maps and imagery
56Content Exchange
57Solutions Content Exchange Infrastructure
- High volume of state/federal requests for local
data - Solving the present-day problems of data sharing
is a pre-requisite to solving the problem of
long-term access - Leveraging more compelling business reasons to
put the data in motion (disaster preparedness,
business continuity, highway construction,
census, ) - Content exchange networks
- Minimize need to make contact
- Add technical, administrative, descriptive
metadata - Establish rights and provenance
58Transfer Modes - Conventional
- CD/DVD
- e.g., 230 CD-ROMs for 1999 Wake County
orthophotos - External drives
- Becoming more routine
- FTP
- Bandwidth intensive restricted to off hours, or
not done - WAN (Wide Area Network)
- Network incompatibilities, network load
- Web Download
- Complex interfaces make automation difficult
59Transfer Modes - Web Services
- WMS (Web Map Service)
- Can only capture derived static images, losing
the underlying data intelligence - Possible use for agent-based image atlas creation
- WFS (Web Feature Service)
- Transfers actual vector data as GML
- Not widely deployed variation in configuration
- Scalability for bulk transfer questionable
- Federal Enterprise Architecture Geospatial
Profile suggests WMS, WFS, FTP
60Repository Development
61Repository Pre-ingest Workflow
62NCGDAP Workflow Data Receipt
63Workflow Format Processing
Conversion
Compound Formats
64Workflow Metadata Processing
Creation
Remediation
65Workflow Ingest Processes
66Extended Curation Feedback and Outreach
67Engaging Spatial Data Infrastructure
68NC Spatial Data Infrastructure NC OneMap
- NC OneMap is a next generation mechanism to
coordinate and disseminate geographic information
in North Carolina and interact with the NSDI. - Objectives
- Build a common
- understanding of North
- Carolina data resources
- Enable widespread
- access and distribution
- of geospatial data
69NC OneMap
- Objectives (cont.)
- Develop ongoing data
- inventory for all geospatial data
- holdings RAMONA
- http//nc.gisinventory.net
- Develop content standards
- for key data themes
- NC Geographic Information
- Coordinating Council (GICC)
- One of the defined characteristics of NC OneMap
is that Historic and temporal data will be
maintained and available.
70Points of Engagement with Spatial Data
Infrastructure
- Framework data communities
- Snapshot frequency, naming schemes,
classification, GML application schemas, format
strategies - Metadata standards and outreach
- Persistent identifiers, versioning, feedback on
metadata quality - Content replication/transfer
- For data improvement projects, disaster
preparedness, aggregation by regional service
providers, and archives - Where does archiving and preservation fit in?
71Emerging Regional Partnerships
- Focused on development of shared infrastructure
for cultivating access to data - Becoming test beds for innovation in the area of
data sharing and data management, including
archiving
72Engaging Industry
73Cultural Changing Industry Thinking
- Is the geospatial industry temporally-impaired?
- Lack of access to older data
- Lack for tool/model support for temporal analysis
- Metadata poor support for changing data
- Education building class projects around
available data (i.e., not temporal) - Increased interest now in temporal applications?
- Increased demand for temporal data?
- Improved tool support ArcGIS 9.2 animation
tools Geodatabase History, etc.
74Project Status
What About Commercial Data?
Cultivating a commercial market for older data.
Part of permanent access is marketing,
advertising, and putting older data into the path
of the user
75Points of Engagement with the Open Geospatial
Consortium (OGC)
- Geography Markup Language (GML) for archiving
(PDF/A version of GML?) - GeoRM (Geo Rights Management)
- Adding preservation use cases
- Content Packaging
- Will there be an industry solution?
- Web Services Context Documents
- Can we save data state as well as application
state? - Content Replication
- Is this a layer in the overall architecture?
- Persistent Identifiers
76Archives Processes
77Maine GeoArchives Project Components
- Retention schedules
- Geospatial data
- Administrative records
- Record accessioning
- Appraisal system
- System documentation
- Archival data and metadata standards
- Rules for disposition of local government records
78Maine GeoArchives Functional Requirements
Adopted set of functional requirements for
recordkeeping systems to insure permanent
retention of data layers
- Compliance
- Responsible
- Credibility
- Completeness
- Authenticity
- Soundness
- Auditability
- Availability
- Exportable
- Renderable
- Redactable
79NC 2006 Survey of Current Archiving Practice
80Question 1 (the filter)
Do you create periodic snapshots of any vector
datasets for long-term retention and archiving?
- Response
- yes 65.3,
- no 34.7
- (out of 57.6
- response rate)
Respondents answering No automatically skip
most of the remaining questions
81Key Results Capture Frequency
82Key Results Formats
83Key Results Formats
84Key Results Metadata
85Key Results Storage
86Key Results Storage
87Key Results Reasons for Archiving
88Conclusion
89Key issues
- What are the points of intersection between
archive needs and business continuity/disaster
preparedness and other business needs? - How to best stimulate and learn from innovation
at the state/regional/local level? - How to make data more preservable from point of
production and on through data transfer - How to most effectively move data in an
efficient, well-documented manner with clarified
rights
90Key issues (continued)
- How to best make Archives a part of spatial data
infrastructure? - How should tradeoffs between level of curation
and quantity of acquisition be made? - Defining the record data vs. derivative
components - How to best cross-fertilize between projects
(NDIIPP, NHPRC, etc.)
91Questions?
Contact Steve Morris Head, Digital Library
Initiatives NCSU Libraries ph (919)
515-1361 Steven_Morris_at_ncsu.edu http//www.lib.nc
su.edu/ncgdap
92Workflow Overview
Handout 1
93Workflow Focus Digital Format Curatorship
Handout 2
94Workflow Focus Geospatial Metadata Management
Handout 3