Published on Apr 04, 2020 | Bikesh Bade | 1617 Views

SoilGrids is a system for global digital soil mapping that uses state-of-the-art machine learning methods to map the spatial distribution of soil properties across the globe. SoilGrids prediction models are fitted using over 230 000 soil profile observations from a series of environmental covariates. 

Maps with a spatial resolution of 250m  of the following soil properties are available: pH, soil organic carbon content, bulk density, coarse fragments content, sand content, silt content, clay content, cation exchange capacity (CEC), total nitrogen as well as soil organic carbon density and soil organic carbon stock.

Data Access

The preview release of  SoilGrids (December 2019) can be accessed through the following services:

WMS: swift access for visualization and data overview.
WCS: best way to obtain map segments for specific regions in the world and to use SoilGrids as input 
     to other modeling pipelines.
WebDAV: download the complete global maps in VRT format.

To download soil data with WMS service and python, first, you need the  Python package for client programming with Open Geospatial Consortium (OGC) web service called OWSLib. Install OWSLib  with PIP

pip install OWSLib

The next step is to call the WMS service to get the map. Soil profile / Map is categorized with different depth so first, you need to list out all the products you need to download in the python list object as:

#sand content data form 0cm to 200cm 
wmssand = ['SNDPPT_M_sl1_250m', 'SNDPPT_M_sl2_250m', 'SNDPPT_M_sl3_250m', 'SNDPPT_M_sl4_250m', 'SNDPPT_M_sl5_250m', 'SNDPPT_M_sl6_250m', 'SNDPPT_M_sl7_250m']

#Clay content data form 0cm to 200cm 
wmsclay = ['CLYPPT_M_sl1_250m', 'CLYPPT_M_sl2_250m', 'CLYPPT_M_sl3_250m', 'CLYPPT_M_sl4_250m', 'CLYPPT_M_sl5_250m', 'CLYPPT_M_sl6_250m', 'CLYPPT_M_sl7_250m']

#pH content data form 0cm to 200cm 
wmsph = ['PHIHOX_M_sl1_250m', 'PHIHOX_M_sl2_250m', 'PHIHOX_M_sl3_250m', 'PHIHOX_M_sl4_250m', 'PHIHOX_M_sl5_250m', 'PHIHOX_M_sl6_250m', 'PHIHOX_M_sl7_250m', 'PHIKCL_M_sl1_250m', 'PHIKCL_M_sl2_250m', 'PHIKCL_M_sl3_250m', 'PHIKCL_M_sl4_250m', 'PHIKCL_M_sl5_250m', 'PHIKCL_M_sl6_250m', 'PHIKCL_M_sl7_250m']

#Coarse content data form 0cm to 200cm 
wmscoarse = ['CRFVOL_M_sl1_250m', 'CRFVOL_M_sl2_250m', 'CRFVOL_M_sl3_250m', 'CRFVOL_M_sl4_250m', 'CRFVOL_M_sl5_250m', 'CRFVOL_M_sl6_250m', 'CRFVOL_M_sl7_250m']

#Slit content data form 0cm to 200cm 
wmsslit = ['SLTPPT_M_sl1_250m', 'SLTPPT_M_sl2_250m', 'SLTPPT_M_sl3_250m', 'SLTPPT_M_sl4_250m', 'SLTPPT_M_sl5_250m', 'SLTPPT_M_sl6_250m', 'SLTPPT_M_sl7_250m']

#carbon content data form 0cm to 200cm 
wmscarbon = ['ORCDRC_M_sl1_250m', 'ORCDRC_M_sl2_250m', 'ORCDRC_M_sl3_250m', 'ORCDRC_M_sl4_250m', 'ORCDRC_M_sl5_250m', 'ORCDRC_M_sl6_250m', 'ORCDRC_M_sl7_250m']

#other content data form 0cm to 200cm 
wmsother = ['BLDFIE_M_sl1_250m', 'BLDFIE_M_sl2_250m', 'BLDFIE_M_sl3_250m', 'BLDFIE_M_sl4_250m', 'BLDFIE_M_sl5_250m','BLDFIE_M_sl6_250m', 'BLDFIE_M_sl7_250m','CECSOL_M_sl1_250m', 'CECSOL_M_sl2_250m', 'CECSOL_M_sl3_250m', 'CECSOL_M_sl4_250m', 'CECSOL_M_sl5_250m', 'CECSOL_M_sl6_250m', 'CECSOL_M_sl7_250m']

#Organic matter data form 0cm to 200cm 
wmssoilOrganic = ['OCSTHA_M_sd1_250m','OCSTHA_M_sd2_250m','OCSTHA_M_sd3_250m','OCSTHA_M_sd4_250m','OCSTHA_M_sd5_250m','OCSTHA_M_sd6_250m']

Now extract the data with required extend as :

#import module
from owslib.wms import WebMapService

#set the wms service url for data extraction
wms = WebMapService('http://data.isric.org/geoserver/sg250m/wcs')

#loop the list of data you want to download
for i in wmssoilOrganic: 
    
    #assign the wms as image with projection 4326(WGS 84) bounding box(bbox) and format geotiff for raster or png, jped as required
    img = wms.getmap(layers=[i],srs='EPSG:4326',bbox=(80, 26, 90, 31),size=(10000, 10000),format='image/geotiff',transparent=True)
    
    #set the location to save data
    location = "/wmsLayers/"+i+".tif"
    
    #write the file 
    out = open(location, 'wb')
    out.write(img.read())
    out.close()

Soil data will be downloaded to the location you have set with the name as extracted for the Soil grid.