Assessing Historical Maps For Characterizing Fluvial Corridor Changes At A Regional Network Scale

Fluvial corridor quality assessment requires that historical data be collected at a regional scale. In this article, our goal is to assess potential map resources to explore riverscape changes at a regional network scale and to define key issues in using an automated vectorization protocol to characterize such changes on such a large scale. We consider IGN's Nouvelle Carte de France a potentially good resource for our objective of two-date (oldest + actual vector database) comparisons on 1:20,000-1:25,000 scale maps, notably when applied at a regional scale. The French IGN corpus is a good example of topographic maps that were produced in the twentieth century in Europe with fairly homogeneous data over a whole national territory. Moreover, the digitization and georeferencing processes applied by IGN are very accurate. The evolution of conventional features is not as significant for the hydrographic theme and should not be a problem for automatic vectorization. The potential temporal coverage is from 1922 to 1993, but the complexity of the sheet divisions, partial revisions, and the heterogeneity of coverage over time prevent multidate analysis.