Global soil hydraulic properties from FutureWater HiHydroSoil v2.0 in an Icechunk Zarr v3 store. Two native EPSG:4326 grids at nominal 250 m resolution: 13 continuous properties and soil texture class on six depth intervals to 200 cm, plus 2-D hydrologic soil group. Includes water retention, saturated hydraulic conductivity, Mualem–van Genuchten parameters, and organic matter. Continuous values are float32 in physical units with NaN for no data; no scaling is required. Texture and hydrologic classes use int16 and uint8, with code mappings in array attributes. Units, CRS, and source provenance are embedded in metadata. Zstd-compressed 64 × 64 spatial chunks in 1024 × 1024 shards support byte-range reads of point profiles and small areas. Mean/mode overviews (2×–256×) support map display. CC-BY 4.0.
Global maps of how soil holds and transmits water, from FutureWater HiHydroSoil v2.0. The data include water content, hydraulic conductivity, organic matter, and soil texture at six depths from the surface to 2 m, plus hydrologic soil groups.
This product stores the maps in Icechunk Zarr v3, so you can read a location or small area without downloading the global GeoTIFFs. Values are in physical units, ready to use. The original grids are preserved, at a nominal resolution of 250 m.
The store is at chill/hihydrosoil/v0.1.0.icechunk/:
The two main groups use separate grids. Both use WGS84 longitude and latitude
(EPSG:4326): x is longitude and y is latitude. Coordinates mark pixel centers,
with latitude running from north to south.
Pixel sizes on the ground vary with latitude. The grids also have different origins, so select locations separately in each group.
Continuous properties are float32 in physical units, with NaN for missing data.
The source scaling has already been applied; no conversion is needed. Soil texture
is int16 with -9999 for missing data. Hydrologic soil group is uint8 with 255
for missing data. Units, class labels, and source information are recorded on each
array; spatial_ref records the coordinate system.
All properties below have six depth layers except hydrologic_soil_group, which
describes the soil profile as a whole.
Water content is a volume fraction: 0.30 m³/m³ means water occupies 30% of the soil volume. The pF value describes how tightly water is held in the soil; higher values represent drier conditions.
The depth_top_cm and depth_bottom_cm coordinates give these boundaries as
numbers. The source's separate topsoil and subsoil summary layers are not included.
For A/D, B/D, and C/D, the first letter applies when the soil is drained; D applies
when it is undrained. Each array has a class_codes dictionary: STC maps codes to
texture names, while hydrologic soil group maps codes to a group and meaning.
The dictionaries cover valid classes; missing-data values are listed above.
Dictionary keys are strings because attributes use JSON. The flag_values and
flag_meanings attributes provide the same class codes in CF format. Xarray
preserves integer codes, including the missing-data values.
Read access is public and requires no credentials. With icechunk, xarray, and
zarr installed, open the store and select a location:
Open hydrologic soil group separately:
Reuse the repository and session for repeated reads.
Arrays are split into small chunks, grouped into larger files called shards. A query downloads only the chunks it needs within each shard.
Chunks are compressed with Zstd. One float32 chunk is 16 KiB before compression.
A native shard in soil_properties holds all six depths, so they can be read together.
Levels 2x through 256x are child groups of both soil_properties and
profile_properties. Each has the same variables and depth labels as its parent,
with coarser coordinates. For example, a 64x pixel spans 64 native pixels in
each direction. Open any level in the same way as the native group:
Pixel sizes are nominal; ground distances vary with latitude. Partial edge blocks are retained, so grid dimensions are rounded up at each level.
Continuous overviews average the available values; class maps use the most common available code. Missing values are excluded. Each level is built from the previous one, so an overview can differ from an average or most-common class calculated directly from the original pixels. Use native pixels for analysis.
The store path identifies product version 0.1.0; the source version is 2.0. New source releases or incompatible layouts use a new store path, leaving earlier versions readable. There is no time dimension; each source release is a separate version of the dataset.
The main branch can change as data are added or corrected. For repeatable
results, save the snapshot ID used by your analysis and reopen that snapshot:
Release tags, such as hihydrosoil-2.0.0, also identify fixed snapshots. Tags are
never deleted or reused; a corrected release gets a new tag with a suffix such
as -r2.
Built from FutureWater's HiHydroSoil v2.0 GeoTIFFs, preserving their original grids. FutureWater estimated the hydraulic properties from soil characteristics using relationships called pedotransfer functions. Some gaps were filled from HiHydroSoil v1.2.
This product restores physical units by dividing continuous source values by
10,000 and preserves integer class codes. Each array records its units, source
version, and source layer name. Validation compares sampled pixels with the
original TIFFs and checks overview calculations independently. Float32 rounding
errors are recorded in the validation reports. The audit location for source
inventories and reports is audit/2.0.0/.
Processing code (MIT licensed): https://github.com/colinahill/hihydrosoil_data
Source data: FutureWater HiHydroSoil v2.0, licensed CC-BY 4.0. Please cite:
Simons, G.W.H., R. Koster, P. Droogers. 2020. HiHydroSoil v2.0 — A high resolution soil map of global hydraulic properties. FutureWater Report 213.
See the data reference for technical details and planned additions for layers outside this product.
ksat | cm/day | Saturated hydraulic conductivity: how readily water moves through saturated soil |
alpha | 1/cm | Parameter α in the Mualem–van Genuchten water-retention model |
n | Dimensionless | Parameter n in the Mualem–van Genuchten water-retention model |
ormc | % | Organic matter content |
stc | Integer code | Simplified FAO soil texture class |
hydrologic_soil_group | Integer code | Runoff classification for the soil profile |
| 618 × 1,236 |
| 32 km |
256x | 239 × 618 | 309 × 618 | 64 km |