## Le SIG comme outil de détection et d’analyse des parcellaires antiques. ## LAC 2014 proceedings, [S.l.], oct. 2016. doi: https://dx.doi.org/10.5463/lac.2014.18 ### Abstract ### The French Rhône valley has traces of ancient roman parcels, testified by antique land registers called “Orange cadastre”. This organisation was highlighted on the left bank of the river and it seems to extend to the other side, in the Tave and Cèze valleys. All this research was conducted in the 80s from the French National Institute of Cartography (IGN) aerial missions using the method of optical filtering. In this study, we intend to use a GIS and the cadastral map in vector format (BDParcellaire® product from IGN). Indeed, the cadastre enables the study of boundaries that have no materialisation in the current landscape. The aerial photographs or topographical maps only give incomplete information, i.e. the perennial human forms or roads, paths, fences, channels, ditches. These documents are selective. The tool used in this study is the histogram of directions. It consists in calculating the azimuth of each parcel boundary and drawing a histogram. The number of boundaries or their total length is shown as a function of the azimuth. The interests of working with the cadastre are that all information are contained in these documents, their precision allows a detailed study of cadastral frames. This method was first validated on previously studied areas and then extended to the Cèze and Tave lower valleys. This helped to detect the presence of “Orange cadastre” in these two valleys, where the method by optical filtering had not delivered convincing results. The use of these vector data for the detection of ancient cadastral frames permits a detailed study of the boundaries structure. The results are encouraging and allow the consideration of new approaches. It would be interesting to combine elevation and topographic data as well as ancient “Napoleonic cadastre” with the aim to eliminate nineteenth and twentieth century boundaries. ### Keywords: ### GIS, Land Registers, Histogram of Directions, Vector Cadastral Map, Orange Cadastre ### Full Text: ### [pdf](https://osf.io/xcbtp) ### Authors #### *Maxime Seguin* Institut National de Recherches Archéologiques Préventives