Towards A Cornucopia Of Place: Diversifying And Simplifying GBH
The existing GBH system has two components: a very complex geographical information system containing the changing boundaries of the counties, districts and parishes of Britain, implemented using the industry standard ArcInfo package but also a large amount of custom code written in Arc Macro Language; and an Oracle database storing c. 30m statistical data values in over 200 separate tables.
The new project will substantially diversify our holdings. Our mapping of changing boundaries will be extended to cover Scotland, and we are also integrating digital mapping of ‘ancient’ parish boundaries, and some sub-parish units, created by another project. These boundaries provide an essential framework for statistical and other content, but do not in themselves tell users anything about past landscapes, so we are adding digital images of two complete editions of Ordnance Survey one inch to the mile maps, the First Series published over the 19th century and the New Popular edition published in the 1940s. These sheets need not only to be image scanned but geo-referenced, relating each sheet to geographical coordinates, and ‘rubber sheeted’: the First Series maps are based on a relatively inaccurate survey, so the scans need to be stretched and compressed to more accurately fit real-world locations. New content also includes the complete texts of three descriptive gazetteers published in the late 19th
Our system must also be simplified and moved towards open standards. Firstly, the web site will be supported only by Oracle, without ArcInfo, and this means the boundary information as well as the image scanned maps and the text must be held within Oracle using specialised subsystems such as Oracle Spatial. Secondly, while we are required to support the Dublin Core we are exploring the use of a number of additional metadata standards designed specifically for spatio-temporal information. Thirdly, and linked to the creation of additional metadata, we are exploring ways to drastically reduce the total number of tables in the system. We both hope and expect that the final system will be heavily used, so performance issues are critical: while database-driven web sites are commonplace, ones based on spatially-enabled databases are less so.