National soil hydrologic groups map of Hungary

The national soil hydrologic groups map of Hungary aggregates the information available from the 100 m resolution 3D soil hydraulic maps of Hungary. The map was derived using k-means clustering combined with expert-based rules. Source data included the national 3D soil hydraulic maps (HU-SoilHydroGrids), maps of basic soil properties (DOSoReMI.hu), maps of salt affected soils, and the Hungarian Detailed Soil Hydrophysical Database (MARTHA). The derived 68 groups are defined by distinct hydraulic properties, including van Genuchten parameters - describing water retention - and saturated hydraulic conductivity. This national map simplifies the representation of complex soil properties to support computationally intensive national-scale models and land management planning. The dataset has a resolution of 100 m and provides full coverage of Hungary. The data is stored in soil_hydrologic_groups.tif, a GeoTIFF file using the Hungarian Unified National Projection System (EOV/HD72 – EPSG:23700; see https://epsg.io/23700). A supplementary CSV file (map_code_cluster_VG_KS.csv) provides definitions of the map codes, including the cluster numbers and their corresponding soil hydraulic parameters. Column descriptions: map_code: map codes map_code_depth: map code with depth interval (e.g., 1_0_5 refers to the 0–5 cm depth of map code 1) cluster_number: cluster number of the soil hydrologic groups thr_VG, ths_VG, alp_VG, n_VG: van Genuchten parameters thr (cm³/cm³), ths (cm³/cm³), alp (1/cm), n (–) KS: saturated hydraulic conductivity (cm/day) The thr parameter was set to 0. The m parameter is equal to 1 - 1/n. The statistics_based_clustering.R file contains the code for the k-means analysis. The code for the expert-based rules is stored in the expert_based_clustering.R file.匈牙利全国土壤水文组地图整合了匈牙利100米分辨率三维土壤水力图谱的全部可用信息。该地图通过K-means聚类结合专家经验规则生成。其源数据涵盖全国三维土壤水力图谱（HU-SoilHydroGrids）、基础土壤属性图谱（DOSoReMI.hu）、盐渍化土壤分布图，以及匈牙利详细土壤水理数据库（MARTHA）。 本次生成的68个土壤水文组由差异化的水力属性定义，包括表征土壤持水性能的范·吉努赫滕（van Genuchten）参数与饱和导水率。该全国尺度地图简化了复杂土壤属性的表达形式，可为计算量繁重的全国级模型与土地管理规划工作提供支撑。 本数据集分辨率为100米，实现了匈牙利全境的完整覆盖。数据以GeoTIFF格式存储于soil_hydrologic_groups.tif文件，采用匈牙利统一国家投影系统（EOV/HD72——EPSG:23700；详见https://epsg.io/23700）。 配套补充CSV文件map_code_cluster_VG_KS.csv提供了地图编码的详细定义，包含聚类编号及其对应的土壤水力参数。 字段说明如下： map_code：地图编码 map_code_depth：带深度区间的地图编码（例如1_0_5代表编码1对应的0–5厘米深度层） cluster_number：土壤水文组的聚类编号 thr_VG, ths_VG, alp_VG, n_VG：范·吉努赫滕参数 各参数的物理意义与单位： thr（cm³/cm³）：残余含水率 ths（cm³/cm³）：饱和含水率 alp（1/cm）：进气压力相关参数 n（–）：孔隙形状参数 KS：饱和导水率（cm/day） 注：thr参数被固定设置为0，模型参数m满足m = 1 - 1/n。 用于K-means聚类分析的代码存储于statistics_based_clustering.R文件，专家经验规则的实现代码存储于expert_based_clustering.R文件。