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Projects – 216,978. Architects – 20,653. Images – 84,293. Institutions - 31. Hits – 42,000 a day. Hits since 2000 – over 11 million. www.philadelphiabuildings.org. All Philadelphia Register Buildings. All PA State Inventory Buildings. All National Register Buildings. - PowerPoint PPT Presentation
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www.philadelphiabuildings.org
Projects – 216,978
Architects – 20,653
Images – 84,293
Institutions - 31
Hits – 42,000 a day
Hits since 2000 – over 11 million
www.philadelphiabuildings.org
All Philadelphia Register Buildings
All PA State Inventory Buildings
All National Register Buildings
All HABS-PABuildings
Geographical Coverage
All 50 States
57 Countries
Baxter’s Panoramic Business Directory, 1859
Rae’s Philadelphia Pictorial Directory & Panoramic Advertiser, 1851
D.J. Kennedy Watercolor, Historical Society of Pennsylvania, K.1-40.1
Green’s Hotel, from Philadelphia Pa., the Book of its Bourse, 1898, p. 67
New Masonic Hall, Wainwright Lithograph Collection, Library Company of Philadelphia
Philadelphia Contributionship fire insurance survey, number 9521
McElroy Directory, 1857
Optical Character Recognition Process
Spreadsheet made from OCR Text
Hexamer & Locher Atlas, 1858, Free Library of Philadelphia
Archival Tiff Format with Color Control, Caption Information and Scale
702 Chestnut Street
Detail of 1858 Hexamer & Locher, illustrating georeferencing with current Philadelphia street centerlines
Centralized Model
CentralData and App
Server(s)GIS
Maps
Demo-graphics
Arch.Drawings
Photos
ScannedMaps
Phila. Dept.of Records,
City Planning,Water Dept.
Athenaeum,Library
Company,HSP,
Phila. Dept. of Records
Athenaeum(PAB)
Athenaeum,Free Library
CML, US Census,research projects
Greater Philadelphia GeoHistory Networkhttp://www.PhilaGeoHistory.org
Centralized Model
• Data stored in one place
• Does not meet local institutional requirements (thus duplicated systems)
• Difficult to plan and scale
• Difficult to agree on standards:– Metadata– Data refreshing– Access control, use agreements
Greater Philadelphia GeoHistory Networkhttp://www.PhilaGeoHistory.org
Centralized Model
• Applications run on centralized servers
• Faster, but must be controlled in one place
Distributed Model
CML PAB
Dept. ofRecords
PACSCL
Demo-graphics
Arch.Drawings
Photos
ScannedMapsGIS
Maps
LandUse
HistoricalContext
PhotoArchives
Phila.Negro
Photos
Applications
Repositories
Data
Greater Philadelphia GeoHistory Networkhttp://www.PhilaGeoHistory.org
Distributed Model• Data stored by each institution (or small group of
institutions)– or in a distributed set of centralized systems
• Can be built using existing systems, or systems designed for other purposes
• Scales by institution• Need to agree on only basic standards:
– Metadata (Dublin Core + Geographic Info)– Protocols for data harvesting
Greater Philadelphia GeoHistory Networkhttp://www.PhilaGeoHistory.org
Distributed Model
• Applications run from anywhere
• Applications can be built as needed for particular projects and by different groups
• Slower (retrieving data from different sources takes time)
• But needed data can be cached (like Google) to provide faster responses
Greater Philadelphia GeoHistory Networkhttp://www.PhilaGeoHistory.org
Data Distribution Approaches• Entirely map-based, GIS systems
– Open Geospatial Consortium (OGC) Web Map Service (WMS)
– Proprietary options (SDEs, ESRI, Google Earth)
• Entirely data-based systems– Open Archives Initiative (OAI)
Protocol for Metadata Harvesting (PMH)– XML gateways, Z39.50, and the rest
Greater Philadelphia GeoHistory Networkhttp://www.PhilaGeoHistory.org
Data Distribution ApproachesMap-based systems• Easier application
development• Wider compatibility
with existing map client software
• Significant entry barriers (cost/server speed) for providers
Data-based systems• Application/network
provides geocoding• Wide support by
existing data server software
• Lower entry barriers for data providers
Greater Philadelphia GeoHistory Networkhttp://www.PhilaGeoHistory.org
The Solution?
• Mixed Network Models– Distributed resources, with centralized
systems where appropriate
• Mixed Data Distribution Approaches– For image-rich base maps (atlas plates, aerial
photography, etc.) – WMS– For data-rich collections (historical photos,
city directories) – OAI + spatial + temporal.
Greater Philadelphia GeoHistory Networkhttp://www.PhilaGeoHistory.org
Challenges
• Metadata Standards – Dublin Core?
• Geospatial and Temporal Metadata– Map extents, feature points– Date and time, both instant and spanned
• Precision, Specificity, and Uncertainty– “702 Chestnut St.” vs. “7th & Chestnut”
vs. “Chestnut St.” vs. “Philadelphia”– “1902” vs. “c. 1900” vs. “Early 20th Century”
Greater Philadelphia GeoHistory Networkhttp://www.PhilaGeoHistory.org
Challenges (cont’d)• Aggregation / Correlation / Change
– Changing place names, boundaries, addresses, and uncertain correlations (city directories)
– Re-aggregating data sets (e.g., census data) to provide useful comparisons over time
• User Interface– Providing useful interaction both to experience GIS
experts, but also to scholars and hobbyists, and even tourists.
Greater Philadelphia GeoHistory Networkhttp://www.PhilaGeoHistory.org