Use of very high resolution (VHR) imagery for control and updating of legal land occupation maps in urban areas.

The ageing of the regional sector pla ns as also the recent changes in map content as defined by the new Walloon code on land planning of 27 November 1997 justify the analysis of new updating methodologies. Most important in regard to the updating strategy to be adopted is the question of the availability of land for additional housing developments. This study therefore focuses on the assessment of available construction sites and some of their characteristics. The study area coves map sheet 50/6 of the Malmedy-Saint-Vith sector. The original method proposed in this case study is based on computer assisted photo
interpretation of digital ortho-photomaps, combined with some sector map information. The method is user-friendly and leads immediately to quantitative assessments, also facilities of conceiving and editing of thematic maps. Further useful information is obtained by combining the map information with a digital terrain model of the area.
Research, on the one hand, confirms the availability of land for additional housing developments, and on the other reveals the consequences of bad urbanisation policies (promotion and development of linear housing developments, insufficient control over quarrying activities, etc.) the "new code" introduces new town planning requirements (more detailed zoning analysis taking into account the environmental aspects, creation of protected areas, impact surveys, ground occupancy estimation) and strengthens the prospect of using this methodology further on.