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Constructing the first municipal-level GIS for France and a multi-modal transport network

Constructing the first municipal-level GIS for France and a multi-modal transport network

Reconstructing administrative boundaries from 1790 to the present

Previous attempts have not succeeded in producing a reliable and accurate database of boundary changes mostly because they did not rely on historical records to reconstruct historical administrative units. As nobody has yet undertaken the painstaking historical reconstruction on a national scale the exact shape and delimitation of French administrative units in the past remain largely unknown. The unique combination of the historical and cartographic expertise of our teams will allow us to fill this major historical gap. Thanks to the seminal work by Séguy and Théré, who compiled a list of all boundary changes since 1801, we have devised a method to reconstruct historical administrative boundaries efficiently and accurately. We will be using a combination of historical and cartographic sources drawing upon administrative records, official maps from both the Service Géographique de l'Armée (SGA) and IGN, and other cartographic material such as cadastral mapping, and recent land surveys. Overall c.15% of all communes, will require exhaustive archival research all over France in order to digitise contemporary maps of administrative boundaries.

Figures (1) to (4): Georeferencing the commune boundary between Louvignies-Bavay and Bavay

BD TOPO boundariesGeorectified map including corrections

(1) BD TOPO boundaries (2) Georectified map including corrections

Drawing historical boundariesResulting GIS boundary

(3) Drawing historical boundaries (4) Resulting GIS boundary

Over the years the Cambridge Group for the History of Population and Social Structure (CAMPOP) has developed significant expertise by reconstructing English and Welsh parish-level boundaries for the period 1831-1881 with sources scarcer than in the French case. The English and Welsh parish and place GIS is now the standard resource used by historians, geographers, archaeologists and economists for mapping historical data for England and Wales, and the GIS shapefiles that resulted from this work have been used by a great number of scholars in very different fields.

Thanks to a team of highly-qualified research associates and research assistants working both in France and in the UK we will put France on an equal footing with other European countries, and will unlock new fundamental comparative and quantitative analyses.

By the end of the research grant we will have produced the first and only set of GIS boundary data for all French communes from 1790 to the present linked to several key demographic, socio-economic and environmental data available at low level. Linking these data to fine spatial units through time and, critically, through them to each other will be a major breakthrough in the application of quantitative analysis of large datasets to French history. This will also enable us to compare spatial and historical variations in those key variables among several countries with a level of details and accuracy never reached before. Finally, our tool will be made available to the entire scientific community providing both transparency and traceability. Through a dynamic database linked to a set of annualised GIS shape files all historical records and maps used to reconstruct boundaries will be built in the data and accessible to all researchers.

Archival work and some case studies

Our work often requires forensic cartographic and archival work to understand complex cases, especially changes that occurred early in the nineteenth century, when non-contiguous communes, enclaves and disputed territories were common occurence.

Case study 1: Tanneron-Callian-Montauroux, three gorgeous hilltop provencal villages, a non contiguous commune and a coal field.