Map Viewing Service (WMS) of the dataset: 10 metre uncertainty band PPRi de Châlons-en-Champagne — CAC sector

The studies carried out in the context of the development of the PPRi de Châlons-en-Champagne (map of hazards) were carried out on the scale of 1/10 000th, and mapped on a background IGN scan25 enlarged to 1/10 000th. Since regulatory zoning stems from the intersection of the hazard map and the stake map, the accuracy of this mapping cannot be greater than that of the hazards. Consequently, the scale of use of the regulatory zoning is that of 1/10 000 and exploitation on a smaller cadastral scale (1/5000 or 1/2000) is not recommended. However, municipalities wishing to do so may transpose the regulatory map into their planning documents provided that they comply with operating principles in order to take account of the uncertainty associated with the expansion of the zoning, particularly at the boundary of the area. Indeed, it is not possible to improve the accuracy of the initial data which presents uncertainty about its contours of the order of 10 metres, which is relatively important on the scale of a plot in an urbanised area. The transposition of the regulatory map into a cadastral planning document cannot therefore be limited to a mere enlargement, which would result in a false precision of the contours. Therefore, a guide defines the principles that would allow municipalities who wish to do so, a transposition into an urban planning document (PLU, municipal map) taking into account the uncertainties between each area. It must also make it possible to define the area regulation to be applied when considering planning permissions. Genealogy: The limits of the uncertainty band are not represented on the PPRi graphic documents, they are not official in nature. The boundaries of the uncertainty band are represented by a polygon straddling the separation between two zones of the regulatory Zonage, its width is 10 metres and it follows neither cadastral nor administrative boundaries. A guide to the interpretation of this band sets out the principles for its operation.针对香槟沙隆市PPRi灾害风险预防计划（原注为灾害地图）开发所开展的研究，比例尺为1:10000，底图采用放大至1:10000比例的法国国家地理研究院（Institut Géographique National，IGN）scan25地理扫描数据。由于监管区划由灾害地图与权属地图叠加生成，因此该区划制图的精度不可能高于灾害地图本身。据此，监管区划的使用比例尺应为1:10000，不建议采用更小的地籍比例尺（如1:5000或1:2000）进行应用。不过，有意向的市镇可将监管地图纳入其规划文件，前提是需遵循相应的操作原则，以考量区划边界扩张相关的不确定性，尤其是区域边界处的不确定性。 事实上，初始数据的精度无法提升，该数据的轮廓边界存在约10米的不确定性，在城市化区域的地块尺度下，这一误差影响相对显著。 因此，将监管地图纳入地籍规划文件的操作，不能仅通过简单放大完成——这会导致轮廓边界出现虚假精度。为此，一份指南明确了相关操作原则，允许有意向的市镇将监管地图转换为地方城市规划方案（Plan Local d'Urbanisme，简称PLU，即市政地图），同时需考量各区域间的不确定性。该指南还需明确，在审批规划许可时应适用的区域监管规则。 数据谱系说明：不确定性带的边界并未在PPRi的图形文档中体现，其本身不具备官方效力。不确定性带的边界由一条跨越监管区划两个区域分界的多边形表示，带宽为10米，且既不与地籍边界重合，也不与行政边界重合。一份针对该不确定性带的解读指南，明确了其应用操作原则。