Big Just Got Bigger!Surprises in managing large map collections
Ian HolmesEDINA
EDINA
delivers online services
Based at Supported by
Vision: To be integral to the quality and productivity of research and education, in the UK and beyond.
Geo-Services
Digimap
• An online mapping and data delivery service• Originally built to provide access to Ordnance Survey
(GB) maps and data - a ‘virtual map library’• Launched in January 2000• Content extended to include:
– Historic OS maps– British Geological Survey data– Marine maps and data (UKHO via Seazone)– Environment data (Centre for Ecology and Hydrology)– Aerial imagery (Getmapping)
• Subscription service with around 65,000 users
Digimap Collections
• Ordnance Survey• Geology• Historic• Marine• Environment• Aerial
Accessing the data: online mapping via Roam
Accessing the data: online mapping via Roam
• Annotation• Data import/export • Save/open• Printing• Measurement tools• No spatial analysis
Accessing the data: forward use
Basket options:• version• format• layers
1: Select area
2: Select data
3: Add to basket
Accessing the data: forward use
• Forward use: Data Download• GIS and CAD users• Access raw data in different formats• Previous versions of data
Digimap for Schools
Digimap for Colleges
Aerial Imagery
• Recent venture with Getmapping• Highest resolution national (GB) dataset: 25cm• Annual updates
Data currency
Data currency
Mosaic – hard edges
Mosaic – data detail
Mosaic – following features
Challenges
• User expectation: now is good
• Sharing data across multiple platforms
Moore’s Law
• Microchip performance doubles every two years
Source: http://www.gotw.ca/publications/concurrency-ddj.htm
Decreasing cost of disk space
Source: http://www.mkomo.com/cost-per-gigabyte-update
Aerial imagery in numbers
• 243,869 1km tiles• 1.7TB• JPEG format
Challenges: mapping
Challenges: mapping
Challenges: mapping
Challenges: printing
Challenges: downloading
Using the data in GIS
• OS MasterMap Building Height Attribute• 25cm aerial imagery• VectorMap Local Raster• OS Terrain 5
Using the data in GIS
OS MasterMap Topography Layer
• Most detailed mapping available
• Supplied in GML format• Provided in GML, DWG and
File Geodatabase formats
Summary
• User expectation/performance– caching
• Currency• Disk space, backup, redundancy
Any questions?