Habitatquarries: distribution of underground marl quarries in the Flemish Region and border areas, with the Flemish distribution of Natura 2000 habitat type 8310

<strong>General</strong> The data source is a geospatial collection of polygons that correspond with the presence or absence of the Natura 2000 Annex I habitat type 8310 (Caves not open to the public) in the Flemish Region (and border areas), Belgium. The dataset contains all known, not collapsed, underground marl quarries in Flanders. Several of these quarries have their entrance in or run underground to the neighboring regions/countries. In general, different polygons represent different quarry units with their own internal climatic environment. Units that cross Flemish borders have been split into separate polygons. Exceptionally they may overlap if such units are situated above each other. For safety reasons, the dataset only contains the contour of the quarries, and no details like floor plans or entrances. For admission to research the indoor climate, please contact the Quarries and Safety Department of the municipality of Riemst (https://www.riemst.be/nl/wonen/groeven; [e-mail]). The data source is produced, owned and administered by the Research Institute for Nature and Forest (INBO, a scientific institute of the Flemish government). <strong>Technical aspects</strong> The data source is a GeoPackage that contains: a spatial polygon layer ‘<code>habitatquarries</code>’ in the Belgian Lambert 72 coordinate reference system (EPSG-code 31370); a non-spatial table ‘<code>extra_references</code>’ with site-specific bibliographic references. The data source has been based on an unpublished shapefile used in De Saeger &amp; Lahaye (2019) and on a BibTeX bibliography file. See R-code in the GitHub repository 'n2khab-preprocessing' at commit c0821eb for the creation. A reading function to return <code>habitatquarries</code> (this data source) in a standardized way into the R environment is provided by the R-package n2khab. The attributes of the spatial polygon layer ‘<code>habitatquarries</code>’ are: <code>polygon_id</code>: a unique number per polygon; <code>unit_id</code>: a unique number for each quarry unit. Quarry units consisting of several polygons (= partly outside the Flemish region) have a number greater than 100; <code>name</code>: name of the site; <code>habitattype</code>: either: <code>8310</code> (habitat type 8310) <code>gh</code> (no Natura 2000 type) missing (outside of the Flemish Region); <code>extra_reference</code>: extra reference with more information. The non-spatial table <code>extra_references</code> provides the bibliography referred to by the spatial attribute <code>extra_reference</code>. It was derived from a BibTeX bibliography file by using the R-package bib2df, and it is back-convertible into one (see R-package n2khab). The original bibliography file is also available in the above linked ‘n2khab-preprocessing’ repository.<strong>一般概况</strong> 本数据集的数据源为一组空间多边形集合，对应比利时佛兰德斯地区（及周边区域）内Natura 2000附件I（Natura 2000 Annex I）生境类型8310（不向公众开放的洞穴）的存在与否情况。本数据集涵盖佛兰德斯地区所有已知且未坍塌的地下泥灰岩采石场，其中部分采石场的入口位于邻近区域/国家，或向地下延伸至邻区。通常而言，不同多边形代表不同的采石场单元，各单元拥有独立的内部气候环境。跨越佛兰德斯行政边界的单元会被拆分为多个独立多边形；特殊情况下，若单元上下叠置，则多边形可能出现重叠。出于安全考量，本数据集仅包含采石场的轮廓信息，未收录平面图、入口位置等细节。如需申请开展室内气候相关研究，请联系里姆斯特（Riemst）市采石与安全部门（https://www.riemst.be/nl/wonen/groeven; [e-mail]）。本数据集由佛兰德斯政府下属科研机构自然与森林研究所（Research Institute for Nature and Forest, INBO）制作、持有并管理。 <strong>技术说明</strong> 本数据集的数据源为地理数据包（GeoPackage）格式文件，包含以下内容：采用比利时Lambert 72坐标系（EPSG代码31370）的空间多边形图层<code>habitatquarries</code>；以及包含站点专属参考文献的非空间表<code>extra_references</code>。 本数据集基于De Saeger & Lahaye (2019)中使用的未公开形状文件（Shapefile），以及一个BibTeX格式参考文献文件构建。其生成代码可参见GitHub仓库<code>n2khab-preprocessing</code>中提交记录c0821eb对应的R代码。 R软件包（R-package）<code>n2khab</code>提供了标准化读取函数，可将本数据集（即<code>habitatquarries</code>图层）导入R环境。 空间多边形图层<code>habitatquarries</code>的属性字段如下： - <code>polygon_id</code>：每个多边形的唯一编号； - <code>unit_id</code>：每个采石场单元的唯一编号。由多个多边形组成（即部分位于佛兰德斯地区之外）的采石场单元，其<code>unit_id</code>值大于100； - <code>name</code>：站点名称； - <code>habitattype</code>：取值可为<code>8310</code>（生境类型8310）、<code>gh</code>（非Natura 2000生境类型），或为空（表示位于佛兰德斯地区之外）； - <code>extra_reference</code>：指向更多相关信息的附加参考文献标识。 非空间表<code>extra_references</code>提供了空间属性字段<code>extra_reference</code>所引用的参考文献列表。该表通过R软件包（R-package）<code>bib2df</code>从BibTeX参考文献文件转换而来，且可逆向转换为BibTeX格式（详见R软件包<code>n2khab</code>）。原始参考文献文件同样可在上述<code>n2khab-preprocessing</code>仓库中获取。