Developing a strategy for PAI at British Waterways

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Developing a strategy for PAI at British
Waterways
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• General Overview of British Waterways
• 2000 mile, 250 year old network of canals and
  river navigations from Somerset to Inverness.
• Leading GI user
• Part of the Central Government SLA
• Wide user base - 1500 users
• Desktop, mobile and intranet GIS
• Small expert community of 10 GIS specialists,
  scattered throughout the organisation.

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• Assessing the impact on BW
• Polygons covering 14000 ha of land
• Network representing 3400km of waterway
• Asset data includes 6000 bridges,
• 1600 locks etc
• 2500 listed structures

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• Assessing the impact on BW
• 70 of all features affected by PAI
• Timescale of Delivery
• 20 by March 2004
• 28 by end of 2005
• 52 by end of 2006

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• The Challenge for BW
• GIS is a primary information source
• Operate a multi-editor environment
• Affected throughout the PAI programme
• Data cannot be left until 2007
• Wish to implement MasterMap

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The Strategy
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• Data Audit
• Part of a wider data quality excercise.
• Is the data affected?
• Is the data fit for purpose?
• Should the data be shifted or recaptured?

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• Data Shift Methodology
• CONSTRAINED RUBBERSHEETING
• Datasets constrained by topological rules.
• Ensures that features share edges.
• Topologies affected across datasets
• ESRI PAITools used to shift the data.
• Uses OS link files to affect rubbersheet shift.
• Allows for easier QA checks - important for
  complex objects and large datasets.

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fig.1. Non-topological data
Nested Poygons with differing numbers of
vertices along a snapped boundary
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fig.2a. Topological data
Adjacent polygons share edges
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fig.2b. Topological data
Topology acts across datasets
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fig.3. Data pre-PAI
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fig.4. Data post-PAI
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Fig.5a. Shifting the Data
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fig.5b. Shifting the Data
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fig.5c. Shifting the Data
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• Planning for Action
• PAI Change management team created.
• Responsible for communication of PAI related
  information.
• To GIS Specialists
• To GI data users - via GIS Specialists and
  intranet service

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Fig6. GISPortal - web-enabled GIS service
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• Planning for Action
• PAI Change management team created.
• Responsible for communication of PAI related
  information.
• To GIS Specialists
• To GI data users - via GIS Specialists and
  intranet service
• With a multi-editor environment detailed
  communication of the PAI datashift programme is
  considered critical.

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• Implementation
• Shift undertaken on frozen snapshot of live
  data.
• Stages involved
• Segment datashift into block areas (by blocks of
  dmus)
• Communicate segmentation and planned freeze date
• Extract data and communicate this action
• Carry out PAI datashift process
• Load POST PAI OS data
• Splice shifted data back into live environment
• Identify this action to data custodian for user
  QA
• Metadata provides information on datashift at
  both dataset and feature level.

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• Conclusions
• Dont stick your head in the sand.
• Use the opportunity as a chance to review your
  data ensure you plan in QA and change
  management processes.
• Dont rush into anything, plan your approach
  carefully and communicate widely.
• Dont hesitate to ask for help