Dataset Direct Download Service (WFS): DDT 70- Isocotes of PPRI n°20160006 Ognon Average Valley Amont

The isocotes of the PPRI are the altimeter values (Z in the NGF 69 marker) of the flood heights calculated for the reference flood. Subject to the rules for constructions and the recommendations to be observed, laid down in the regulation of the PPRI, isocotes make it possible to calculate the altimetry of the highest waters which should be observed for the installation of an authorised construction. This height is calculated as follows: Z = (a * z2 + b * Z1)/(a+b) with Z1 = nearest isocot of highest value, Z2 = closest isocot of the lowest value, a = distance between the Z point and the Z1 isocot measured perpendicular to the isocot route, B = distance between the Z-point and Z2 isocot, measured perpendicular to the isocot route. A schematic generally makes this formula explicit in the appendix to the PPRI presentation note.防洪风险规划（PPRI）中的洪水等高线（isocote），为基准洪水计算所得的洪水高度对应的高程值，即以NGF 69高程基准为参照的高程值Z。依据PPRI规章中规定的建筑施工规则与需遵守的相关建议，此类等高线可用于计算经许可的建筑施工所需观测的最高洪水高程。该高程的计算公式如下： Z = (a·Z₂ + b·Z₁)/(a+b) 其中，Z₁为数值最高的相邻等高线，Z₂为数值最低的相邻等高线，a为Z点与Z₁等高线之间沿等高线走向垂直方向测得的距离，b为Z点与Z₂等高线之间沿等高线走向垂直方向测得的距离。 PPRI说明文档的附录中通常配有示意图，对该公式进行详细阐释。