The common agricultural policy is one of the most important policies of the European Community. Common agricultural policy mechanisms include the direct payments, which represent a steady income for farmers and have a positive impact on the preservation of agricultural production and preservation of cultural landscape in Slovenia.
Data of actual land use of agricultural and forest land currently represent basic source for determining eligibility for obtaining direct payments and is updated on the basis of national orthophotos in three-year cycles. In some areas information about actual land use is more than three years old, which causes problems in the process of determining eligibility for direct payments. It is therefore necessary to introduce an alternative source of information about the actual situation in the area and to optimize the data maintenance process.
Automatic procedures for identification of land cover changes using various remote sensing data have unexploited potential to improve the quality of data on the actual land use of agricultural and forest land. The usage of automated processes for classification of land use changes can also contribute to the efficiency of the maintenance procedures. The results of this project will contribute to up-to-date status and quality of the actual land use to reduce irregularities in the agricultural beneficiaries’ reports for individual measures of the common agricultural policy.
Up-to-date status of actual land use of agricultural and forest land is closely linked to the availability of state orthophotos, which are produced in the national projects of the Cyclical aerial photographing of Slovenia (CAS). Actual land use of agricultural and forest land is updated yearly for the part the national territory for which aerial images and ortophotos were produced in that year (CAS was carried out). Aerial photography is carried out in a period of two to four years, in exceptional circumstances this period may be extended, due to for example adverse weather conditions at the time of recording. Thus, the state orthophotos as a primary source of information for updating the actual land cover use of agricultural and forest land, sometimes do not meet the requirements regarding to up-to-date status. Possible solution is to use the alternative sources for actual land use updating, like remote sensing data, such as optical satellite imagery, radar imagery and lidar data.
Updating actual land use of agricultural and forest land is based on photointerpretation of state orthophotos and numerous auxiliary data. Updating is conducted in two steps; in the first step each polygon is reviewed and, if necessary, updated by operator – photointerpreter. In the second step, the updated data are confirmed and, if necessary, corrected by the operator – controller. This two-step updating process provides quality data, but it needs a lot of human and time resources. Updating procedure may now be improved by the introduction of at least partially automated methods in the production line. This means the introduction of partly automated classification of land use changes, so that operator would check only areas identified as potential change areas. In this procedure operator makes targeted updating, he checks and corrects only the areas where this method has automatically detected changes. In this way we can optimize the data updating process.
This research project explored the use of alternative data sources and partially automated maintenance procedures to ensure the effective data updating process of actual land use of agricultural and forest land. Our focus was automatic identification of key changes in actual land use of agricultural and forest land: the reforestation of agricultural land, the urban area expansion on farmlands, the deforestation in forests, area changes in orchards and vineyards. The results of the automatic classification of changes are designed in the way that they can be directly used by end users in the process of actual land use updating and in the control measures under the common agricultural policy.
The basic goals of the project were:
- to explore the use of alternative satellite and airborne remote sensing data for use in the process of determining eligibility to obtain direct payments;
- to develop a methodology for the automatic identification of changes in the actual land use;
- to design the layer of spatial changes of the actual land use with the aim to improve the up-to-date status of the actual land use as a primary source for determining eligibility for obtaining direct payments.
The final goal of the project was to produce “Operational instructions for the use of alternative remote sensing sources and the automatic identification procedure of the land use changes in the updating process of actual land use of agricultural and forest land”. In these instructions the methodology is described how the automatic processing of alternative data sources can be incorporated in updating procedure of actual land use of agricultural and forest land.
Therefore, results of this research are significant for:
- direct applicability of the methodology in the existing process of the Ministry of agriculture, forestry and food in the updating of data layer of actual land use for determining eligibility for the acquisition of direct payments to farmers;
- automatic identification of land use changes and thus fewer manual checks in mass data verification;
- faster acquisition and higher quality of data changes for the actual use of agricultural and forest land, which are necessary for the implementation of the common agricultural policy.