Abstract
This paper describes the application of geographic information system methodology in the appraisal—as an approach on a strategic scale—of the characteristics of a territory likely to be affected by new land transportation infrastructures across particularly sensitive areas. The chosen scope of study covers the Pyrenean region, which marks the border between France and Spain and is considered one of Europe's richest enclaves from an environmental viewpoint. The analysis focuses on the identification of areas where induced impact on the environment could be higher and therefore where focus should be placed on the assessment. This focus was made possible by the construction of an environmental quality map—through the integration of a number of theme maps for different environmental variables—covering the entire area under study. At the same time, a calculation model was built to determine the accessibility before and after construction of the proposed transportation infrastructures. The combination of accessibility and environmental quality maps provides useful results to improve the strategic environmental assessment process by incorporation of indirect effects. To discuss the likely implications of a rise in accessibility and as a test for the indicator used, an analysis of land use changes for the period from 1992 to 2004 has also been done for a smaller area where a motorway was built in the late 1990s; this analysis provides an idea of the potential development of the area and a good amount of data for discussion.