Dartford Borough Council (DBC) has started to amend its GIS data due to the Positional Accuracy Improvement (PAI) programme undertaken by the Ordnance Survey (OS). The Council has over 200 digital map datasets with the largest two being the property boundaries (BLPU extents) and the Planning Application boundaries.

DBC has had a corporate GIS system for over ten years. Nearly all the required data had been captured onto an old UNIX ArcInfo workstation. This data was captured using software that was considered state of the art at the time; subsequently the data capture tools within GIS have improved but DBC has not migrated accordingly. There were a number of errors within the data that meant that if the layer was shifted using PAI software, the errors within the layer would just be propagated to the shifted information and possibly made worse.

As with many local government organisations, DBC was not in a position financially or technologically to make a full software purchase.  Instead they opted for a 1Spatial Local Government Data Cleaning solution.  1Spatial’s consultants took DBC’s data and ran it through Radius Topology software, correcting the vast majority of the common errors in the data automatically.  This also meant a rapid turnaround, ensuring minimal interference with the council’s work and a quick solution before the PAI programme commenced.

The process has improved the current data and helped to reduce the number of errors that have occurred during the PAI shift. This has reduced the number of ‘easy’ polygons that require further checking. The output files have helped DBC to focus on areas within the data that need further improvement and allowed the Property Information team to release PAI-adjusted data to the users more quickly than expected.

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www.dartford.gov.uk