Scottish Integrated Administration and Control System (SIACS)

EU member states are required to establish an IACS to ensure their portion of CAP funding is allotted correctly. All land parcels in receipt of subsidy must be mapped to within a tolerance of ±1.5 m for perimeter and ±5% or ±1 ha (whichever is the smaller) for area. Spatial surveys take place each year (usually around January) to account for chainging field boundaries due to e.g. changes of land ownership. The land use questionnaire itself is then usually completed during the subsequent May/June to coinicde with the Agricultural Census.

The Scottish IACS data distinguishes over 300 agricultural land classes based on information obtained directly from land managers. Each year, a small proportion of the farms submitting claims are audited to ensure the information provided is accurate. Note that the land use classes have changed slightly over time to reflect the changing nature of agricultural subsidies. This effect is particularly prominent in the data prior to 2009 and may present problems for the robust identification of land use trends.

Where fields contain multiple land uses, the area of each must be reported. Note, however, that the spatial distribution of land use within a field is not recorded - the smallest spatial data unit within IACS is the field. Database users should also be aware of the occasional presence of multiple claims for the same parcel of land, which may arise when several farm businesses share e.g. an area of common grazing.