Conference Paper

Soil information is of great importance for decision makers, the general public and environmental scientists as soils are an important natural resource providing key ecosystem services. Soil information can be presented as single profile point data, as thematic layers generated using digital soil mapping methods or by conventional soil mapping. The most important factor, however, in soil information, besides quality, uncertainty information and lineage, is its proper access.

GSIF (Global Soil Information Facilities) is a framework developed by ISRIC - World Soil Information and partners for collecting, generating and sharing soil information. SoilGrids is a collection of global soil property and class maps developed under GSIF. The thematic layers were generated based on field information from over 100,000 locations for soil properties and classes, such as soil taxonomy, pH, organic carbon,depth to bedrock, bulk density, texture and cation exchange capacity. The thematic dataset is distributed in GeoTiff format at a resolution of 1km (0.00833 degrees), for six different soil depths and with measures of uncertainty (mean, 90% prediction limits). The uncompressed dataset for the world is around 250 gigabytes and freely accessible at http://www.isric.org/content/soilgrids.

SoilGrids API is a REST interface to the dataset. The API is divided into major core functionalities: Stream and Query. Stream resources allow for developers to download specific local area sections (tiles) based on specific tile ID. Search for specific tiles is possible using tile_with_point function where the tile ID is returned based on an intercepting query point. Query resources allow for point spatial query of dataset returning a GeoJSON with soil attributes for different depths and confidence levels. The resources support data filtering (e.g. only upper depth values or just one attribute). SoilGrids API REST follows a discovery/description design inspired by OGC Webservices (e.g. Web Processing Service), with self-descriptive resources for stream (GET:stream/describe) and query (GET:query/stream), internet media types and support for HTTP OPTIONS and HEAD request methods. CORS (Cross-Origin Resource Sharing) support is also enabled.

The API is currently used by the http://soilgrids.org website and the new SoilInfo app that is under development. ISRIC - World Soil Information invites mobile phone developers, GIS users, programmers and researchers to use the API as a standard source to access and retrieve local and global soil data, and welcomes collaboration.