Big Just Got Bigger! discusses the challenges of managing large map collections through the Digimap service. Digimap provides access to geospatial data from various sources, including Ordnance Survey, British Geological Survey, aerial imagery, and more. It has grown significantly over time to include more data sources and users. Managing such large datasets and meeting user expectations of current data and performance presents challenges. Issues include keeping data current while sharing across platforms, disk storage needs increasing exponentially over time, and ensuring data can be accessed and used through various tools and formats.

1. Big Just Got Bigger!
Surprises in managing large map collections
Ian Holmes
EDINA

2. 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.

3. Geo-Services

4. 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

5. Digimap Collections
•Ordnance Survey
•Geology
•Historic
•Marine
•Environment
•Aerial

6. Accessing the data: online mapping via Roam

7. Accessing the data: online mapping via Roam
• Annotation
• Data import/export
• Save/open
• Printing
• Measurement tools
• No spatial analysis

8. Accessing the data: forward use
Basket options:
• version
• format
• layers
1: Select area
2: Select data
3: Add to basket

9. Accessing the data: forward use
• Forward use: Data Download
• GIS and CAD users
• Access raw data in different formats
• Previous versions of data

10. Digimap for Schools

11. Digimap for Colleges

12. Aerial Imagery
• Recent venture with Getmapping
• Highest resolution national (GB) dataset: 25cm
• Annual updates

13. Data currency

14. Data currency

15. Mosaic – hard edges

16. Mosaic – data detail

17. Mosaic – following features

18. Challenges
• User expectation: now is
good
• Sharing data across multiple
platforms

19. Moore’s Law
• Microchip performance doubles every two years
Source: http://www.gotw.ca/publications/concurrency-ddj.htm

20. Decreasing cost of disk space
Source: http://www.mkomo.com/cost-per-gigabyte-update

21. Aerial imagery in numbers
• 243,869 1km tiles
• 1.7TB
• JPEG format

22. Challenges: mapping

23. Challenges: mapping

24. Challenges: mapping

25. Challenges: printing

26. Challenges: downloading

27. Using the data in GIS
• OS MasterMap Building Height Attribute
• 25cm aerial imagery
• VectorMap Local Raster
• OS Terrain 5

28. Using the data in GIS

29. OS MasterMap Topography Layer
• Most detailed mapping
available
• Supplied in GML format
• Provided in GML, DWG and
File Geodatabase formats

30. Summary
• User expectation/performance
– caching
• Currency
• Disk space, backup, redundancy

31. Any questions?