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September 2003 |
What did the OpenGIS Consortium ever do for us?
The input an organisation has into OGC specifications can vary according to their expertise and subject knowledge. In terms of impact on the data and systems used in the industry, a useful metric is to view which organisations have actually implemented OGC specifications in their software or services. Implementation is a pre-cursor to conformance where OGC has ratified an implementation via accredited conformance test.
GI and GIS users should be wary of any claims of 'OpenGIS compliance'. This is an erroneous claim, which is sometimes used by parties who may have some association with, but no technical accreditation from, OGC. Caveat emptor!
what has OGC ever done for us?
Having established that the OGC is a large and growing consortium of industry bodies, dedicated to the advancement of ‘spatial interface specifications’, the average GIS 'man on the street' may not realise that this work is starting to filter into mainstream GIS and spatial data provision.
In the UK, the most publicised OGC 'product' has been the adoption of Geography Markup Language (GML 2.0) by Ordnance Survey (GB) as a means to supply OS MasterMap data. This has been a bold departure, as GML is a vendor neutral format. It is voluminous in comparison to National Transfer Format (NTF) and it is the first dataset of national coverage to adopt the specification. This will impact on nearly every use of GI in Great Britain due to the precedent Ordnance Survey (GB) set and due to the consequences it will have for large-scale data users. By adopting GML, Ordnance Survey (GB) have given themselves the opportunity to 'clean' and reconstitute the much berated NTF OS Land-Line, giving users much better base data. This is of course at a cost, to them and to their users and software partners. It has, however, forced the GI industry a step further towards mainstream Information Technology by the use of XML (eXtensible Markup Language) based document types and definitions i.e. GML. GML has also been adopted and approved as the standard for geospatial data exchange within the UK Government's electronic-Government Interoperability Framework (e-GIF).
Fig 2a Traditional ‘non interoperable’ GIS
Other specifications, which are borne by OGC are also receiving increased recognition and use within the UK. The OGC Simple Features specification (vector geometry) is at the core of GML. Furthermore, OGC's Grid Coverages specification is also growing in stature as more vendors adopt interfaces to raster data providers who are adopting the tenets of OGC. The widespread adoption of database technology to store geometric data is also being accelerated and coupled through OGC SQL92 specifications.
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