Case studies of GI use in Defra
GI is used in a wide range of policy and delivery areas accross the Department. Examples include the flexible provision of information about rural communities, enabling public participation in the mapping of Open Access Areas, supporting commitment to tackle Environmental Noise, modeling the impact of Climate Change and monitoring trends in Sustainable Development. The Rural Payment Agency has also created a GI-based Rural Land Register (RLR) based on detailed Ordnance Survey mapping, as part of the process of modernising scheme administration. More detailed examples are included below:
Rural Payments Agency - Mapping of Single Farm Payment scenarios
The introduction of the Single Farm Payment has impacted different farm sectors to a greater or lesser extent. Analyses for the Defra Economics and Statistics Directorate showed the effects of two different payment options. Each holding was given a positive or negative value reflecting changes in subsidy that the holding might attract based on its farm type. These values were aggregated to district level to show which parts of the country would have a net gain or a net loss of subsidy payments.
Fig 1 – losses and gains in subsidy payments by Local Authority Districts
Distribution and land use of small fields
Little information exists on the land use and distribution of small fields (<=2 hectares), in England. The Defra Sustainable Agriculture Unit required a better understanding of the abundance and distribution of such small fields. An analysis exercise was undertaken, utilising subsidy payment data and the Agricultural Census. The analysis demonstrated the distribution of small fields geographically and by farm type and also explored the correlation between field size and the distribution of farms across different economic groups.
Fig 2 – Density distribution of small fields (< =2 hectares)
Slope maps
One of the factors influencing susceptibility to soil erosion is the gradient of the terrain. Land height data, originally collected to help identify areas vulnerable to flooding, can be used to generate slope maps (figs 3 & 4). This information can be used to help encourage land use that is compatible with steep slopes. Natural England are using this information to identify areas of upland heather that should not be burnt to prevent the creation of bare ground on steep slopes.
A further example (fig 5) shows the mapping of ‘grips’ using a digital terrain model. Grips constitute drainage channels cut into moorland. Grips can accelerate soil erosion thereby causing siltation in streams, rivers and reservoirs. Better management of grips can alleviate their impact on the aquatic environment.
Fig 3 - Map identifying areas of slope greater than 11o (20%)
Fig 4 - Fields with slope greater than 11o identified over aerial imagery and a DTM
Fig 5 - Grip channels displayed over aerial imagery and a DTM
Page last modified: 7 February 2007
Page published: 7 February 2007