Polaris 30m Probabilistic Soil Properties US¶
Probabilistic Remapping of SSURGO (POLARIS) soil properties—a database of 30-m probabilistic soil property maps over the contiguous United States (CONUS). The mapped variables over CONUS include soil texture, organic matter, pH, saturated hydraulic conductivity, Brooks-Corey and Van Genuchten water retention curve parameters, bulk density, and saturated water content.
|theta_s||saturated soil water content||m3/m3|
|theta_r||residual soil water content||m3/m3|
|ksat||saturated hydraulic conductivity||log10(cm/hr)|
|ph||soil pH in H20||N/A|
|lambda||pore size distribution index (brooks corey)||N/A|
|hb||bubbling pressure (brooks corey)||log10(kPa)|
|n||measure of the pore size distribution (van genuchten)||N/A|
|alpha||scale parameter inversely proportional to mean pore diameter (van genuchten)||log10(kPa-1)|
Citation & Related Publications¶
Read the original paper here and cite the work using
Chaney, Nathaniel W., Budiman Minasny, Jonathan D. Herman, Travis W. Nauman, Colby W. Brungard, Cristine LS Morgan Alexander B. McBratney, Eric F. Wood, and Yohannes Yimam. "POLARIS soil properties: 30‐m probabilistic maps of soil properties over the contiguous United States." Water Resources Research 55, no. 4 (2019): 2916-2938.
POLARIS provides a spatially continuous, internally consistent, quantitative prediction of soil series. It offers potential solutions to the primary weaknesses in SSURGO: 1) unmapped areas are gap-filled using survey data from the surrounding regions, 2) the artificial discontinuities at political boundaries are removed, and 3) the use of high resolution environmental covariate data leads to a spatial disaggregation of the coarse polygons.
The dataset is available at varying depth from surface, while the statistics provided include mean, mode , median and percentile values, only median values have been included as part of the collection created.
|Depth from Surface|
Overall datasets include processing approximately 80,000 files which have been converted into individual images within a collection per property at varying depth. So for example collection bd_mean includes bd_0_5 and represents a single image for contiguous US with bd value at surface depth of 0-5 cm from surface.
Notes from Data providers¶
05/01/2019 - The variables hb, alpha, ksat, om are in log10 space.
05/01/2019 - Due to file size constraints, the 1 arcsec database is split into 1x1 degree tiffs. Each variable/layer/statistic has its own virtual raster that acts as the "glue" of all the smaller 1x1 degree chunks. For more information on virtual rasters see https://www.gdal.org/gdal_vrttut.html.
06/02/2019 - The variables hb and alpha were originally reported to have the units of log10(cm) and log10(cm-1) respectively. This was a typo. The correct units are log10(kPa) and log10(kPa-1) respectively.
Earth Engine Snippet: HiHydro Additional Layers¶
var bd_mean = ee.ImageCollection('projects/sat-io/open-datasets/polaris/bd_mean'); var clay_mean = ee.ImageCollection('projects/sat-io/open-datasets/polaris/clay_mean'); var ksat_mean = ee.ImageCollection('projects/sat-io/open-datasets/polaris/ksat_mean'); var n_mean = ee.ImageCollection('projects/sat-io/open-datasets/polaris/n_mean'); var om_mean = ee.ImageCollection('projects/sat-io/open-datasets/polaris/om_mean'); var ph_mean = ee.ImageCollection('projects/sat-io/open-datasets/polaris/ph_mean'); var sand_mean = ee.ImageCollection('projects/sat-io/open-datasets/polaris/sand_mean'); var silt_mean = ee.ImageCollection('projects/sat-io/open-datasets/polaris/silt_mean'); var theta_r_mean = ee.ImageCollection('projects/sat-io/open-datasets/polaris/theta_r_mean'); var theta_s_mean = ee.ImageCollection('projects/sat-io/open-datasets/polaris/theta_s_mean'); var lambda_mean = ee.ImageCollection('projects/sat-io/open-datasets/polaris/lambda_mean'); var hb_mean = ee.ImageCollection('projects/sat-io/open-datasets/polaris/hb_mean'); var alpha_mean = ee.ImageCollection('projects/sat-io/open-datasets/polaris/alpha_mean');
You can download the datasets here: http://hydrology.cee.duke.edu/POLARIS/
POLARIS is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
Curated by: Samapriya Roy
Keywords: Digital soil mapping, Soil, Environmental modeling, High performance computing
Last updated dataset: 2019-05-04
Last curated: 2022-03-05