Pontoise, Napoléonien Parcels (1815)

The commune of Pontoise is covered by the Napoleonic cadastre in 16 section sheets, all at 1:1250 scale. The sheets have been digitized by the Archives départementales du Val-d'Oise which keeps the originals. Each sheet has been trimmed and then recalibrated in relation to the Bd Topo of the IGN. A reasoned geometric recalibration, based on georeferencing and intended to correct the topometric inaccuracies of the document was carried out with the aim of obtaining a visual correspondence of the objects between the document and the current reference frames (Bd Topo, Open street map, current Cadastre base). The set of 16 sheets was then digitally assembled to obtain a single document offering continuous coverage of the entire municipality. The 16 georeferenced documents as well as the cadastral mosaic are distributed in the form of a georeferenced file in the WGS84-Pseudo Mercator (EPSG3857) projection system in JP2000 format (downloadable document) compatible with most spatial data management tools or in the form of data streams that can be integrated directly into these same tools. The Napoleonic Cadastre is a mapping operation decided in 1807. It was the first systematic operation on a French scale, with the objective of "measuring more than one hundred million parcels, classifying them all according to the degree of fertility of the soil, evaluating the taxable product of each of them, and gathering the parcels that belong to each owner" (Gaudin Law 1807). This vast and highly codified operation (cadastral code of 1808) was completed in the 1850s. For each commune, registers and an atlas composed of sheets at 1:250 (sometimes 1:500 or 1:200) referencing all of the land entities was executed. The Napoleonic Cadastre is a reference document for the study of pre-industrial spaces since it records the state of development of the territories at the beginning of the 19th century and is, by its overall topometric quality, generally quite accurate geometrically. It is also systematic in its content: plots, roads, odonyms, toponyms, hydrological network, buildings... etc. It can therefore easily be set in a current reference frame with margins of error that are sometimes small (these margins generally depend on the topographic environment: the rougher the territory, the less accurate it is. For Pontoise, the overall margin of error is about 2 m). Its qualities also make it possible to make the link with older documents whose forms, often still present in the cadastre, can be transferred at sight into the geometric space of the Napoleonic period, which is itself easily "calibrated" in a current geometric space. This document has been vectorized manually (L. Costa) to be able to be processed spatially. A transformation was also carried out to obtain a layer on the parcels and their status, namely: built, light built, communication, Hydro, Parcel.

庞托伊斯公社被纳入拿破仑时期的土地登记系统中，共分为16张分区图，所有图均按照1:1250的比例尺绘制。这些图经过瓦勒德瓦兹省档案馆的数字化处理，该档案馆保留了原始文件。每张图经过裁剪并在与IGN的Bd Topo进行关联后进行了重新校准。基于地理参照的合理几何校准，旨在纠正文件的拓扑不准确性，以期实现文档与当前参考框架（Bd Topo、Open street map、当前土地登记基础）中对象视觉上的对应。16张图的集合随后被数字化拼接，形成了一份覆盖整个市政区的连续文档。16个地理参照文档以及土地登记镶嵌图以WGS84伪墨卡托（EPSG3857）投影系统的地理参照文件形式（可下载文档）发布，兼容大多数空间数据管理工具，或以数据流形式直接集成到这些工具中。拿破仑时期土地登记是1807年决定的一项测绘操作，它是法国规模上的首次系统性操作，其目标是“测量超过一亿个地块，根据土壤肥力对所有地块进行分类，评估每个地块的应税产品，并收集属于每个所有者的地块”（高丁法，1807年）。这一庞大且高度规范化的操作（1808年的土地登记法典）于19世纪50年代完成。对于每个公社，编制了登记册和由1:250（有时为1:500或1:200）比例尺的图页组成的图集，这些图页引用了所有土地实体。拿破仑时期土地登记是研究前工业化空间的重要参考文件，因为它记录了19世纪初领土的发展状态，并且由于其整体拓扑质量，在几何上通常相当精确。其内容也具有系统性：地块、道路、街道名称、地名、水文网络、建筑物等。因此，它可以轻松地置于当前参考框架中，误差范围有时很小（这些误差通常取决于地形环境：地形越崎岖，误差越小。对于庞托伊斯，整体误差约为2米）。其质量也使得与较旧文件的联系成为可能，这些旧文件的形式，通常仍存在于土地登记中，可以直观地转移到拿破仑时期的几何空间中，而拿破仑时期的几何空间本身也易于在当前几何空间中进行“校准”。该文档已由L. Costa手动矢量化，以便进行空间处理。还进行了一项转换，以获得地块及其状态的图层，包括：建筑用地、轻度建筑用地、交通用地、水域、地块。