Dataset Direct Download Service (WFS): Zone Aléa surfacique PPRN of the ransom and Fontenelle basin of the Seine-Maritime department

Area exposed to one or more surfacial hazards represented on the hazard map used for risk analysis of the RPP. The hazard map is the result of the study of hazards, the objective of which is to assess the intensity of each hazard at any point in the study area. The evaluation method is specific to each hazard type. It leads to the delimitation of a set of areas on the study perimeter constituting a zoning graduated according to the level of the hazard. The allocation of a hazard level at a given point in the territory takes into account the probability of occurrence of the dangerous phenomenon and its degree of intensity. For multi-random PPRNs, each zone is usually identified on the hazard map by a code for each hazard to which it is exposed. All hazard areas shown on the hazard map are included. Areas protected by protective structures must be represented (possibly in a specific way) as they are always considered subject to hazard (case of breakage or inadequacy of the structure). Hazard zones can be described as developed data to the extent that they result from a synthesis using multiple sources of calculated, modelled or observed hazard data. These source data are not concerned by this class of objects but by another standard dealing with the knowledge of hazards. Some areas within the study area are considered “no or insignificant hazard zones”. These are the areas where the hazard has been studied and is nil. These areas are not included in the object class and do not have to be represented as hazard zones. However, in the case of natural RPPs, regulatory zoning may classify certain areas not exposed to hazard as prescribing areas (see definition of the PPR class).本类定义为暴露于一种或多种地表灾害，且被纳入用于RPP风险分析的灾害地图的区域。 灾害地图源自灾害专项研究，其核心目标为评估研究区域内任意点位的各类灾害强度。不同灾害类型对应专属的评估方法，据此可在研究范围内划定一系列区域，形成按灾害等级分级的区划体系。对某一地域点位分配灾害等级时，需综合考量危险现象的发生概率及其强度量级。 针对多随机PPRNs，通常会在灾害地图上为每个区域赋予其所暴露的各类灾害对应的专属编码。 所有灾害地图上标注的灾害区域均需纳入本类范畴。受防护结构保护的区域亦需（可采用特定标注方式）予以体现，因这类区域始终被视为存在灾害风险，例如防护结构发生破损或效能不足的情形。 灾害区域可被描述为经加工整合的数据集，其源自对多源计算、建模或观测所得灾害数据的综合合成。此类源数据不属于本类对象的管辖范畴，而是由另一项针对灾害认知的标准进行规范。 研究区域内部分区域被归类为“无灾害或灾害可忽略区域”，即经专项研究确认灾害强度为零的区域。这类区域不属于本类对象范畴，亦无需作为灾害区域予以标注。但针对天然RPPs，监管区划可能将部分未暴露于灾害的区域划定为指令性区域（prescribing areas），详见PPR类（PPR class）的定义。