Résumé 3rd expert workshop 2011

On 11 July 2011 an expert workshop was held at the Leibniz Institute of Ecological Urban and Regional Development to discuss ways to capture data on land usage as well as changes in land use. The participants agreed that official land-use surveys in their current form are neither sufficient nor suitably detailed to reflect the structures of land use and their development, particularly the consumption of land for settlement development and new transport infrastructure. Information on the size and dominant usage of land parcels as noted in land cadastres was never designed to serve as a basis for land-use statistics. Even today, the current form of land use is frequently not indicated. Hence, new roads or restored mining areas, for example, may only be recognized by the cadastre after a delay of several years. In addition, the measurement of land consumption is hindered by the ongoing migration of base data to the new ALKIS system. In view of the political goal of reducing land consumption for settlement and transport purposes, reliable figures are urgently required to better estimate the current situation and to evaluate remedial measures. This was repeatedly emphasized by representatives of the Saxon Ministry of the Environment and Agriculture as well as the Ministry of the Interior.

Against this backdrop, the participants at the workshop considered whether other sources of base data are more suitable for such analysis, and how these could be used for the quantitative determination of land use. Here, topographical data, in particular ATKIS Basis-DLM, comes to the fore. Unlike cadastral data, such geodata does not describe the earth’s surface in terms of forms of ownership, but rather according to its physical characteristics.

In the meantime, official topographical maps are already being derived from this data source. Furthermore, such data is regular updated and scrutinized for changes in actual land use.

New roads, in particular, can be quickly recognized, i.e. they are reflected in the data only three months (at the latest) after their construction.

Proof has already been given of the better suitability of such topographical data for estimating the spatial extent of different forms of land usage. The first results can already be seen in the Monitor of Settlement and Open Space Development (IOER Monitor). The Monitor aims to provide spatial information in the form of a wide range of indicators to help evaluate the sustainability of land use in Germany. The focus here is rather on the actual form of land cover, particularly in open space, rather than the specific form of land usage.

This perspective reflects the condition of the earth’s surface (e.g. the extent of soil sealing through built-up structures or roads in a target area) better than considering land usage only. Of course, there are also problems in handling ATKIS Basis-DLM. Currently, the model used to classify topographic objects into types of land cover, the definition of classes as well as the modelling of roadways is being revised in view of the workshop discussions. Furthermore, the ATKIS Basis-DLM has been affected by the creation of a new data model under the so-called AAA Project. This has the effect of hindering temporal comparison. The new model should be implemented by all 16 Länder by 2013, accompanied by a systematic report of errors arising through the pre- and post-migration of the models. Reliable estimates of indicators on this base data should then be possible.