Historic Landscape Characterisation (HLC) is a technique that allows the classification and presentation of historic aspects of broad landscapes. HLC is regularly used to support management, enjoyment, protection and planning, or to stimulate more detailed research.
Prior to the National HLC (NHLC) project, virtually all of England had been characterised through individual HLC projects, but these were at county or sub-regional level, with each of the studies using slightly different methodologies and categorisation methods. In early 2016, Natural England appointed Exegesis to compile a national HLC dataset, drawing together the existing sub-regional HLC datasets and applying a common framework, structure and terminology to a new unified dataset. The aim of the project was to improve the awareness, understanding, appreciation and ability to manage and monitor the historic dimension of England’s landscape at a national scale, for both professional and non-professional end-users.
The database containing the terminology applied to all the different sub-regional datasets was cleaned and then the original terms used were mapped to a bespoke thesaurus, created to ensure that all could be mapped to a suitable, equivalent new term. The associated spatial data was also processed so that the irregular polygons were firstly imported to a merged dataset and then generalised into a gridded dataset. The gridded approach eliminated discrepancies in polygon size or accuracy, and overcame issues where there were small amounts of missing data in the original datasets.
The final gridded dataset was produced at 500m and 1000m scale, with each grid cell having a single associated record with information about the historic landscape character types (both broad types and narrower, character types) and period information. The datasets can be viewed and interrogated in GIS software packages, and when viewed alongside other datasets, the NHLC data can act as an indicator of historic landscape character and can therefore feed in to decisions about landscape management, planning, heritage asset management or research priorities.
Further information from Abby Hunt.