Map Viewing Service (WMS) of the dataset: Risks of the PPRi de la Loire val d’Orléans (upstream)

Area exposed to one or more 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).本数据集类涵盖的区域，是指用于RPP风险分析的灾害图（Hazard Map）上标注的、遭受一种或多种灾害影响的区域。该灾害图源自灾害专题研究，其核心目标为评估研究区域内任意点位处各类灾害的强度。针对不同灾害类型，需采用专属评估方法，据此在研究范围内划定一系列区域，形成按灾害等级分级的分区区划。在研究区域内某一给定点位分配灾害等级时，需综合考量该危险现象的发生概率及其强度等级。针对多随机PPRNs，灾害图上的每个分区通常会通过其对应暴露灾害的专属编码进行标识。灾害图中展示的所有灾害区域均需纳入本类范畴。由防护结构保护的区域亦需进行标注（可采用特定方式），因为此类区域始终被视为处于灾害风险之中（例如防护结构发生破损或失效的情形）。灾害分区可被视为衍生数据，其生成需基于对多源计算、建模或观测所得的灾害数据进行综合处理。本类对象不涉及上述源数据，相关源数据需遵循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划定为"no or insignificant hazard zones"，即经研究确认灾害影响为零的区域，此类区域无需纳入本类对象范畴，亦无需作为灾害分区进行标注。但针对天然RPP而言，监管区划可将部分未受灾害影响的区域归类为规定区域（详见PPR类(PPR Class)的定义）。