Tertiary isohypes top

The isohypsin cards are part of Flanders’s Quartair and Tertiar cards. Isohypses represent the relief of the base of Quartarian deposits, which is the same as the top of the Tertiary deposits. The elevation lines are an overlay of the lithoprofielytpitch maps. The systematic mapping of the Quartaire and Tertiary Geological Laws on a scale of 1: 50000 in Flanders, commissioned by the Flemish Region, was launched in 1993. For a more detailed description, see https://www.dov.vlaanderen.be/page/quartair等高程线图件（isohypsin cards）属于佛兰德斯地区第四纪与第三纪图件的组成部分。等高程线（isohypses）用于表征第四纪沉积物基底的地形起伏，该基底与第三纪沉积物的顶面高程相一致。该高程线为岩性倾角图（lithoprofielytpitch maps）的叠加图层。由佛兰德斯地区委托开展的、比例尺为1:50000的佛兰德斯地区第四纪与第三纪地质图系统填绘工作于1993年启动。如需获取更详细的描述，请访问https://www.dov.vlaanderen.be/page/quartair