The power of the HLA dataset lies in its utility as both a quantitative and qualitative tool that can be used as a complete dataset, broken down into smaller units for analysis (such as by Local Authority or Landscape Character Areas) or queried to extract particular categories, periods or types of land use. The GIS dataset can be interrogated in a range of ways, which can be understood as follows:
• Location-based or Spatially, such as ‘what are the land uses in this area?’
Data can be selected based on the spatial relationship of HLA polygons to features in any other dataset - for example, selecting all records within a given radius of a particular asset.
• Type-specific or Attribute-based, such as 'where are there occurrences of this particular type, category or period?'
This extracts information from the dataset based on the text stored in the GIS attribute table. Query statements can be developed to return entries based on type, category or period – or any combination of the three.
Using HLA data in GIS
If a user has an interest in a particular type, as in this example which focuses on Designed Landscapes, there are a variety of approaches to gaining the fullest information that the HLA dataset can provide. Of course, how a query is carried out will differ depending on a range of specific requirements an individual user might have. However, this should provide a useful starting point.
The basic functions of different GIS packages, including data querying, are largely the same. Nevertheless, the arrangement of each user interface and indeed sometimes even the names of the functions do differ. For this reason this summary is a guide to general principles, and not a manual for any particular GIS package.