Prussian Card Recording NW 1: 25 000, new photo 1891-1912

Over a period of almost 50 years since the beginning of the country’s inception, the original recordings had not been reproduced, even because of the lack of military and civilian interest. It was only around 1860 that the interest of the civil side changed. Especially on the side of mining there was a real desire for maps in scale 1: 25.000. From 1868 onwards, the General Staff made these card sheets available to the Prussian Ministry of Commerce, which were originally intended to be used only for the derivation of follow-up scales. However, since the now published map sheets had already been included between 1836-1850 and only 20 years later without further updates, they were rejected in some parts of Prussia. In the following years, the call for current maps became more and more urgent. The foundation stone for the new recording was laid. From 1875 onwards, the entire Prussian territory was re-incorporated, now in the unit of measurement agreed by the International Meter Convention of 1875. Only the blade cutting, the projection and the scale were taken over from the primordial table sheets. Terrain reproduction was no longer carried out in a snap representation, but for the first time in the form of height-layer lines, whereby a level area called normal zero was introduced as the reference point for a uniform elevation indication throughout Germany. Compared to the original recording, this new recording clearly shows the modern cartographic design principles, such as the structure of the road network, the representation and limitation of vegetation, the reproduction of the administrative districts, the inscription and the edge of the leaf, which still characterise the content and appearance of the official topographical map works. The production method was mainly the engraving on copper or the drawing on lithography stone. Originally, the new recording had its own numbering system, which was later adapted to the sheet numbers and sheet names of today’s DTK25 for reasons of simplification.在该国建国以来近50年的时间里，原始测绘记录始终未被复刻，究其缘由甚至包括军方与民间均缺乏相关兴趣。直到1860年左右，民间层面的测绘需求才出现转变。尤其是矿业领域，对1:25000比例尺（scale 1:25.000）的地图产生了切实需求。自1868年起，总参谋部（General Staff）将这些图幅提供给普鲁士商业部，而这批图幅原本仅设计用于推导后续比例尺的地图产品。但由于现已公开的这批图幅早在1836至1850年间就已编制完成，时隔20年后才推出且未进行任何更新，因此在普鲁士部分地区遭到了拒收。在此后的数年中，社会对现势性地图的诉求愈发迫切，全新测绘工作的基石就此奠定。自1875年起，整个普鲁士领土被重新测绘，此次采用了1875年国际米制公约（International Meter Convention of 1875）所约定的计量单位。仅图幅裁切、投影方式与比例尺沿用了原始图幅的设定。地形表示不再采用快速手绘的表现手法，而是首次采用分层色带线（height-layer lines）进行表达；同时引入了被称为“正常基准面（normal zero）”的高程基准，作为全德国统一高程标注的参照基准。相较于原始测绘成果，这套全新的测绘产品清晰体现了现代地图制图设计原则，例如道路网的结构梳理、植被的表示与边界限定、行政区划的呈现、注记设置以及图廓设计——这些原则至今仍是官方地形图作品的内容与外观特征的核心。其制作工艺主要为铜版雕刻与平版石印。最初这套全新测绘成果拥有独立的编号体系，后出于简化需求，被调整为与现今DTK25一致的图幅编号与图幅名称。