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?