Dutch grid map layers for biodiversity surveys

This dataset contains map layers in GeoPackage format with the following grids used in biodiversity surveys in the Netherlands: Layer name Size (m) Description IvonGrid Kwartierhok 1250x1042 Used between 1902 and 1950 by IVON botanical surveys. IvonGrid Uurhok 5000x4168 Used between 1902 and 1950 by IVON botanical surveys. Each square contains 16 'kwartierhok' squares with corresponding first four characters in column name. RdGrid Kilometerhok 1000 Used since 1950 in biodiversity surveys. RdGrid Uurhok 5000 Used since 1950 in biodiversity surveys. Each square contains 25 kilometer squares. The RdGrid maps are available in the WGS84 and RD New (EPSG:28992) spatial reference systems, as they are aligned to rounded RD coordinates. IvonGrid is only available in WGS84. Grid square codes Kilometerhok (1x1 km) and Uurhok (5x5) grids have corresponding grid square codes. A code consists of three concatenated numbers for map sheat (1-62), 5 km square (11-58) and 1 km square (11-55). E.g. a 5 km square code looks like 4017. In literature and on collection labels this often written as 40.17 or 40-17. Maintanance This dataset is being curated by FLORON Plant Conservation Netherlands since 1988 for use in botanical surveys (previously by Theo Peterbroers, Bart Vreeken and Ruud Beringen). History IVON stands for "Instituut voor Vegetatie-onderzoek Nederland", an NGO founded in 1930 was most active until the 1950's and then succeeded by FLORON in 1988. More information about the repartition of the IVON grid can be found in Atlas van de Nederlandse Flora part 1 (Mennema et al. 1989). The original map was hand drawn on topographical maps by J.W.C. Goethart en W. J. Jongmans (Van Ooststroom 1956) originally following the Bessel 1841 projection (EPSG:7004). The grid cells are equal in size, although not rounded to kilometers. The size was probably chosen to fit maps that were commercially available at that time. References Mennema, J., Quene-Boterenbrood, Plate, C. L., Van der Meijden, R., & Weeda, E. J. (1989). Atlas van de Nederlandse flora. Kosmos, Amsterdam. van Ooststroom, S.J. (1956). Het I.V.O.N. – Werk. Correspondentieblad ten dienste van de floristiek en het vegetatie-onderzoek van Nederland 1: 2–3.本数据集包含采用GeoPackage格式的地图图层，涵盖荷兰生物多样性调查中使用的以下网格系统： 图层名称 尺寸（米） 说明 IvonGrid Kwartierhok 1250×1042 1902年至1950年间由IVON（Instituut voor Vegetatie-onderzoek Nederland）开展植物调查时使用。 IvonGrid Uurhok 5000×4168 1902年至1950年间由IVON开展植物调查时使用。每个正方形包含16个“kwartierhok”方格，其列名的前四个字符对应该方格。 RdGrid Kilometerhok 1000 1950年起用于生物多样性调查。 RdGrid Uurhok 5000 1950年起用于生物多样性调查。每个正方形包含25个1km方格。 RdGrid地图支持WGS84与RD New（EPSG:28992）两种空间参考系统，因其对齐于取整后的RD坐标。IvonGrid仅支持WGS84参考系统。 网格方格编码 Kilometerhok（1×1km）与Uurhok（5×5km）网格配有对应的方格编码。编码由三组连续数字组成，分别对应地图幅面（1-62）、5km方格（11-58）与1km方格（11-55）。例如，5km方格编码形如4017，在文献与采集标签中常写为40.17或40-17。 维护情况 本数据集自1988年起由荷兰FLORON植物保护协会负责管护，此前由Theo Peterbroers、Bart Vreeken与Ruud Beringen维护，主要用于植物调查工作。 背景说明 IVON是一家成立于1930年的非政府组织，全称为"Instituut voor Vegetatie-onderzoek Nederland"，活跃至20世纪50年代，后于1988年由FLORON接手。有关IVON网格划分的更多信息可参考《荷兰植物区系图集》第一卷（Mennema等，1989）。原始地图由J.W.C. Goethart与W. J. Jongmans在地形图上手绘完成（Van Ooststroom，1956），最初采用贝塞尔1841投影（EPSG:7004）。网格单元格尺寸统一，但未取整至千米级别，其尺寸选择或为适配当时市面可购的地图规格。 参考文献 1. Mennema, J., Quene-Boterenbrood, Plate, C. L., Van der Meijden, R., & Weeda, E. J. (1989). 荷兰植物区系图集. 阿姆斯特丹：Kosmos出版社. 2. van Ooststroom, S.J. (1956). IVON的工作. 《荷兰植物区系与植被研究通讯》1: 2–3.