FAQ - WoSIS

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What is WoSIS?
Which soil properties are standardised in WoSIS?
Towards soil harmonisation?
How should the WoSIS datasets be cited?
What do the attribute codes mean?
What measures for 'fitness-for-intended-use' are provided?
How can I access data derived from WoSIS?
What is the WoSIS data-sharing policy?
How can I help improve WoSIS and SoilGrids?
Who provided soil profile data for the WoSIS effort?
What if I could not find an answer to my question?
Acknowledgements
Main sources

Schematic WoSIS workflow for ingesting, standardising and dissiminating soil profile (point) data

What is WoSIS?

WoSIS^TMstands for 'World Soil Information Service', a large database based on PostgreSQL + API's, workflows, dashboards etc., developed and maintained by ISRIC, WDC-Soils. It provides a growing range of quality-assessed and standardised soil profile data for the world. For this, it draws on voluntary contributions of data holders/providers worldwide.

The source data come from different types of surveys ranging from systematic soil surveys (i.e., full profile descriptions) to soil fertility surveys (i.e., mainly top 20 to 30 cm). Further, depending on the nature of the original surveys the range of soil properties can vary greatly (see here).

The quality-assessed and standardised data are made available freely to the international community through several webservices, this in compliance with the conditions (see Letters of Agreement) specified by the various data providers.

For additional details about WoSIS please click here.

Location of soil profiles provided with WoSIS latest (see also dashboard)

Which soil properties are standardised in WoSIS?

We presently standardise the following soil chemical properties (organic carbon, total carbon, total carbonate equivalent, total nitrogen, phosphorus (extractable-P, total-P, and P-retention), soil pH, cation exchange capacity, and electrical conductivity) and physical properties (soil texture (sand, silt, and clay), bulk density, coarse fragments, and water retention), grouped according to analytical procedures (aggregates) that are operationally comparable (see list).

When specified by the data providers, additional information is provided on the analytical methods themselves (e.g. class size limits for soil textural fractions or the fine earth fraction; methods (e.g. pipette or hydrometer) as well as dispersion agents). For mapping, especially at (sub)national level, such methodological differences should be considered carefully, as indicated in the documentation, under 'towards' full harmonisation. It is up to the users themselves to assess which information should be considered in their specific applications. Unfortunately, as indicated, the desired level of detail is often not provided in most source databases. As a result, it is difficult to assess the 'fitness-for-intended-use' of the individual data themselves (see Van Leeuwen et al, 2021 and 2024).

For each profile, we provide the original soil classification (FAO, WRB, USDA, and version) and horizon designations insofar as these have been specified in the source databases.

Measures for positional uncertainty (i.e. location) of the point data as well as a first approximation for the uncertainty associated with the operationally-defined analytical methods and date of description/sampling are presented, for possible consideration in digital soil mapping and subsequent earth system modelling.

For a short description of procedures and data access see here.

Towards soil harmonisation?

According to the Global Soil Partnership, "Harmonization could be seen as a next step to standardization, where parties agree to apply a standard as the central concept to which soil data and information are translated." Full data harmonization in a global context, the ultimate goal of WoSIS, is a daunting task. It will first become feasible once results of extensive, comparative proficiency testing programmes become available, for example in the framework of Pillar 5 of the Global Soil Partnership and GLOSOLAN (Global Soil Laboratory Network), and a common set of ’international’ reference methods Y , where Y is a defined standard operating procedure (SOP, for example ISO-SOP, GLOSOLAN-SOP or ICPF-SOP), has been accepted and endorsed by the international soil community. For a broader discussion see this ISRIC report. Once available for specified soil types or soil landscapes, such pedotransfer functions may be applied to the standardised data provided by WoSIS. The resulting data sets, with associated measures for uncertainty, should be stored as separate datasets of soil properties 'harmonised as if measured according to method Y.' It should be noted, however, that decisions as to whether full harmonization is necessary for mapping a given soil property can be influenced by the resolution of the mapping itself as well as the desired precision and accuracy of the predictions.

How should the WoSIS datasets be cited?

We serve both static snapshots as well a dynamic version of the WoSIS-derived soil properties for the world.

Where data represent a substantial contribution to a scientific paper, citation may involve formal inclusion of the WoSIS-developers as co-author(s) in accordance with scientific standards.

Required citations are as follows:

a) Snapshots should be cited in accord with the DOI of the accompanying data paper:

Batjes NH, Calisto L and de Sousa LM, 2024. Providing quality-assessed and standardised soil data to support global mapping and modelling (WoSIS snapshot 2023). Earth Syst. Sci. Data Discussion. https://doi.org/10.5194/essd-2024-14
Batjes NH, Ribeiro E, and van Oostrum Ad, 2020. Standardised soil profile data to support global mapping and modelling (WoSIS snapshot 2019). Earth Syst. Sci. Data https://doi.org/10.5194/essd-12-299-2020
Batjes NH, Ribeiro E, van Oostrum A, Leenaars J, Hengl T and Mendes de Jesus J, 2017. WoSIS: providing standardised soil profile data for the world. Earth Syst. Sci. Data 9, 1-14. https://doi.org/10.5194/essd-9-1-2017

b) Wosis_latest layers should be cited in accord with the following examples:

For individual datasets (please adapt per dataset):

Batjes NH, Calisto L and de Sousa LM, 2024. WoSIS latest - Water retention volumetric - 500 kPa. ISRIC Soil Data Hub resource identifier: 2f99e11b-183c-11e9-aba8-a0481ca9e724. Date downloaded: 15/01/2024.
For whole 'wosis-latest' dataset:

Batjes NH, Calisto L and de Sousa LM, 2024. WoSIS-latest: Standardised world soil profile data. ISRIC Soil Data Hub resource identifier: https://tinyurl.com/39xhaa9d. Date downloaded: 15/01/2024.

What do the attribute codes mean?

File naming conventions, descriptions and units of measurement used in the latest release of WoSIS ('wosis_latest' i.e. 'wosis_public' version) or are detailed here.

What measures for 'fitness-for-intended-use' are provided?

We provide three measures for 'fitness-for-intended-use' of the standardised soil profile (point) data:

Positional uncertainty.
Attribute accuracy (variability, expressed as coefficient of variation).
Age of data (date the profiles were described/sampled).

The above measures may be considered when calculating the accuracy of digital soil maps and of any interpretations derived from them. Further information is provided in the following data paper.

How can I access data derived from WoSIS?

Standardised profile data (with 'public' licenses, i.e. CC-BY or CC-BY-NC) derived from WoSIS are distributed in two ways. The most recent, latest (dynamic) version can be accessed through an OGC-compliant WFS (Web Feature Service). Further, snapshot (static) dataset(s) in TSV (tab separated values) format with a DOI are provided for consistent citation purposes.

The most recent WoSIS release can be accessed through the following services:

WoSIS_latest: This dynamic dataset contains the most recent complement of standardised soil data served from WoSIS. Being dynamic, this dataset will grow once new point data are acquired and standardised, additional soil properties are considered, and/or when possible amendments are required.

The data can be accessed through an OGC-compliant WFS (Web Feature Service); for this, enter the following WFS link (http://maps.isric.org/mapserv?map=/map/wosis_latest.map) directly in your GIS application.

For an overview of layers served, please go to the ISRIC Soil Data Hub. Alternatively, for a generalised overview see the wosis_latest dashboard, or use the GraphQL API to easily query the data (see below under Tutorials).
Snapshots: These static datasets, in TSV format, are a representation of the complement of standardised data available at a given moment. Each snapshot is given a unique name and digital object identifier (DOI) for consistent citation purposes. The last snapshot is: "December 2023'. Generally, a new snapshot will be prepared when some 40,000-80,000 new profiles have been shared with us for standardisation and/or the range of soil properties standardised has increased substantially. The next snapshot release is foreseen in mid 2026.
Webplatform: Allows to view, query/explore and download WoSIS-latest point data (as well as SoilGrids layers, version 2020).

Tutorials:

Accessing 'wosis_latest' from QGIS, see tutorial.
Accessing 'wosis_latest' from R, see tutorial.
Querying/exploring 'wosis_latest' using GraphQL API, see tutorial.

What is the WoSIS data sharing policy?

Standardised data served from WoSIS are freely accessible, provided the source of the standardised data (i.e., version) is duly acknowledged.

The data license specified by the various data providers is indicated in the database itself; this may be CC BY or CC BY NC. Datasets with a more restrictive CC-license are not served to the international community, yet some of these can be used by ISRIC for SoilGrids applications based on a more specific license agreement with our centre. SoilGrids products, however, are always made freely available to the international community (see FAQ - SoilGrids).

Data are provided to users under the general terms and conditions of the ISRIC software and data policy.

How can I help improve WoSIS and SoilGrids?

To improve SoilGrids predictions for your country or region, please consider contributing soil profile data for standardisation in WoSIS.

Note that ISRIC will always respect the data policy of the data provider and will not publically share any data unless written permission is given to us to do so.

If you wish to share soil profile data for consideration/processing in WoSIS please see here for additional information.

We particularly welcome datasets that also include duplicate measurements so that we may refine our procedures for quantifying the uncertainty in wet chemistry data (see Van Leeuwen et al. 2020), and ultimately in soil data derived from spectrometry, in WoSIS.

Agencies and/or experts that contributed data are gratefully acknowledged as a contributing organisation on our website.

Who provided soil profile data for the WoSIS effort?

WoSIS draws on a large collection of geo-referenced soil profile data for the world. Populating WoSIS has been made possible thanks to the contributions and shared knowledge of a steadily growing number of data providers. We are grateful for their contributions (see acknowledgments).

What if I did not find an answer to my question?

If you have a technical question about WoSIS that is yet not answered in this FAQ, please post it to our 'Google group'. For this, please register first at WoSIS user group. ISRIC staff will be automatically notified of any new questions arising. Using the group will make it easier for other WoSIS-users to find quality answers to their questions.

Alternatively, if you have a technical question about SoilGrids that is not answered in this FAQ, please post it to GIS.StackExchange, under the tag soilgrids. ISRIC staff are subscribed to this tag and will be automatically notified of any new question arising. GIS.StackExchange makes it easier for other SoilGrids users to find quality answers to their questions.

Acknowledgements

WoSIS is funded from ISRIC's core funding (Netherlands Government).

A wide range of agencies and experts have provided data for the WoSIS/SoilGrids effort; we gratefully thank them for their contributions.

Main sources

Batjes NH, Calisto L, and de Sousa, L.M (2024). Standardised soil profile data to support global mapping and modelling (WoSIS snapshot 2019). Earth System Science Data Discussion, 46 pp. https://doi.org/10.5194/essd-2024-14
Batjes NH (2023). Options for harmonising soil data obtained from different sources. ISRIC - World Soil Information, Wageningen, 20 pp. doi: 10.17027/isric-wdc-6ztd-eb19
Batjes NH and van Oostrum AJM (2023). World Soil Information Service (WoSIS) ̶ Procedures for standardizing soil analytical method descriptions. ISRIC - World Soil Information, Wageningen, 46 p. https://doi.org/10.17027/isric-1dq0-1m83
Batjes NH, Ribeiro E, and van Oostrum Ad (2020). Standardised soil profile data to support global mapping and modelling (WoSIS snapshot 2019). Earth System Science Data,12, 299–320. doi: 10.5194/essd-12-299-2020
Batjes NH, Ribeiro E, van Oostrum A, Leenaars J, Hengl T and Mendes de Jesus J (2017). WoSIS: providing standardised soil profile data for the world. Earth Syst. Sci. Data 9, 1-14. doi:10.5194/essd-9-1-2017
Calisto L (2023). ISRIC GraphQL web services for WoSIS and ISIS data access, ISRIC - World Soil Information. https://graphql.isric.org/
De Sousa, LM (2023). WoSIS Data Model 2023 (Documentation). https://git.wur.nl/isric/databases/wosis-docs/-/blob/main/README.md
Ribeiro E, Batjes NH and van Oostrum AJM (2020). World Soil Information Service (WoSIS) - Towards the standardization and harmonization of world soil data. Procedures Manual 2020. ISRIC Report 2020/01, ISRIC - World Soil Information, Wageningen, 166 p. doi: 10.17027/isric-wdcsoils.202001

[Note: The WoSIS data model was updated to the ISO 28258 domain model in 2023 hence parts of the PM2020 are now outdated]
van Leeuwen CCE, Mulder VL, Batjes NH and Heuvelink GBM (2021). Statistical modelling of measurement error in wet chemistry soil data. European Journal of Soil Science, doi: 10.1111/ejss.13137
van Leeuwen CCE, Mulder VL, Batjes NH and Heuvelink GBM (2024). Effect of measurement error in wet chemistry soil data on the calibration and model performance of pedotransfer functions. Geoderma 442, 116762. https://doi.org/10.1016/j.geoderma.2023.116762

Contact:

WoSIS team