Slicker OS MasterMap® imports and updates with GeoConcept Modules

Users of the GeoConcept geographic information system from Kingswood MapMechanics can now take fuller advantage of the features of the advanced OS MasterMap range of digital map data from Ordnance Survey.

Using automated processes developed by MapMechanics, it is now possible to import periodic OS MasterMap “change-only” updates seamlessly into the core dataset; to remove duplicate objects where overlapping sections of mapping are being used; and to reposition user-defined objects that may have been slightly misplaced on earlier, less accurate maps.

MapMechanics has also adapted its Fast Compressed Mapping system to create compressed maps from OS MasterMap map datasets. Typically an FCM dataset can reduce a OS MasterMap dataset to around half the previous size, while retaining the essential elements of the original.

OS MasterMap is Ordnance Survey’s major new large-scale digital map framework, based on Britain’s National Grid, and developed specifically for use on computers and in geographic information systems.

It includes a mass of detailed information such as the exact location of building outlines, roads, pavements – even details as small as post boxes. It is becoming increasingly popular as a basis for GIS work and embedded mapping in other applications.

Since the underlying map data is constantly evolving, users can opt to receive periodic updates of data that has changed. Now MapMechanics has built a GeoConcept module which reconciles the updates with the core data held by the user. It takes the new data, extracts it from the compressed GML (Geographic Markup Language) format in which it is supplied, compares the identities of all the new map “objects” in it with those in the existing database, and replaces the previous items without disturbing the rest of the data.

Users working on large-scale maps of adjacent areas will appreciate MapMechanics’ new de-duplication utility. In order to display large irregular shapes (for instance, a 200m corridor surrounding a meandering underground cable), it is often necessary to work on several slightly overlapping areas of mapping, in which some objects may be duplicated.

Now MapMechanics has developed a GeoConcept utility which identifies objects that are held in common in two areas of data, and suppresses the duplicate items to give a true picture of the features in the terrain. It has been helped in developing this process by the fact that every item in the OS MasterMap dataset has its own unique 16-digit reference, or TOID (Topographic Identifier).

Another new set of tools allows users to reposition objects that may have been slightly misplaced on earlier maps. A key feature of the OS MasterMap dataset is the introduction of Positioning Accuracy Improvement (PAI), which allows objects to be placed more precisely at their true grid reference points. But this poses a potential problem for users who may have digitised the position of their own assets on older, smaller-scale or less accurate maps , and may find that they appear in the wrong place on OS MasterMap maps. For instance, a pipeline might be shown on the wrong side of a hedge.

MapMechanics’ system examines the way users’ assets were positioned in relation to pre-existing features on earlier maps, notes any changes in the location of these features in the OS MasterMap data, and repositions the assets in correct juxtaposition to the features on the new maps.

The final new development in MapMechanics’ current launch is Fast Compressed Mapping for OS MasterMap. FCM mapping allows very large map datasets to be compressed for use in applications where data storage capacity is at a premium – for instance, on mobile computing devices. Now this process can be applied to OS MasterMap data, broadening the range of applications for which it is appropriate.