PAI Adjustment and Data Cleansing

The Ordnance Survey commenced a programme of improving the accuracy of their 1:2500 rural mapping in 2001. As a result, data that had been captured to match the earlier mapping does not necessarily match the modern equivalent.

Data Insight offer a simple yet thorough and effective solution to these issues which does not necessarily incur great expense.

Many software companies preach the virtue of using fully automated software as being the total answer. However, for many years we have digitised data using a mixture of automated and manual approaches.

We still believe this to be the most thorough and best possible approach to resolving the PAI issues as it has a strong element of human interpretation.

Our method is simple, the result - the highest standard one can achieve!

Our method has five stages:

Stage 1 - the data is initially validated to identify anomalies such as polygons poorly captured to OS mapping and other erroneous features. Where features are poorly digitised, these are initially cleansed to match the mapping perfectly.

Stage 2 - using OS link files the data is automatically shifted to its new position using ESRI UK's PAI software tools.

Stage 3 - the newly positioned data is accurately snapped to the new map base using Data Insight bespoke software 'AutoSnapper'.

Stage 4 - 100% of the shifted features are checked by our own staff to ensure the accuracy of the snapping and shifting processes.

Stage 5 - alignment of the newly positioned data is compared to the alignment of the original data using comparative software developed by Data Insight. Any resulting anomalies are corrected where necessary.