Address Layer 2 Gazetteer Searches

GGP 2009 has full support for overlays stored in geospatial databases Oracle Locator, SQL Server 2008 and PostGIS. Almost all the features that our users expect to find in a file-based overlay are available when database storage is used. This includes the ability to perform gazetteer searches on an indexed database table.

This article will demonstrate how we can create an overlay that exposes the OS MasterMap Address Layer 2 dataset, and how to configure it for gazetteer searches on address fields. The only pre-requisite is to have Address Layer 2 loaded into a database using the GGP MasterMap Loader application.

Using the ATFEdit Setup program, we need to create a point overlay that connects to the table ADDRESSPOINT, contained in the MasterMap database. If we use SQL Server 2008, remember to disable the SafeSpatialQueryMode by going into the “Advanced” parameters editor. The application will detect that the table has multiple character fields indexed , which makes it suitable for gazetteer searches.

In the “Gazetteer” tab, select up to seven fields to search on. The ones I have chosen are:

• Organisation
• SubBuildingName
• BuildingName
• BuildingNumber
• Thoroughfare
• PostTown
• PostCode

Once the layer is ready, we can perform gazetteer searches as usual:

Read more: AddressLayer2, MasterMap, OrdnanceSurvey