The document outlines the metadata requirements for soil profiling and sampling as part of a global mapping initiative, including details on methods, analysis, upscaling, and data collection challenges. It specifies the total number of sampling locations (929,042) and the density of data across various countries, as well as sampling periods and methods. Additionally, it highlights the biggest challenges faced by countries in data collection and future mapping updates.

2. Metadata
in the GSOС map
Konstantin Viatkin
GSP Secretariat

3. Metadata collection form

4. Metadata content - source data
• Total number of soil profiles/sampling locations;
• Type of sampling (profiles/augers/topsoil);
• Number of locations for each sampling method;
• Sampling Period (e.g. 1980-2007)
• Georeferencing (GPS coordinates/Location names);
• Depth of sampling
• Sampling design (e.g. transect, catena, land use etc.)

5. Metadata content - analysis methods
• Methods - Soil Organic Carbon analysis;
• Methods - Bulk Density (measured/estimated)
• Details about the sampling;
• Pedotransfer functions, default values, citations;
• External datasets (HWSD, SoilGrids.org);
• Methods - Coarse Fragments (measured/estimated/NA)
• Coarse fragments unit (e.g. % volume / % weight)
• Peat (sampling and description method);

6. Metadata content - upscaling
• Upscaling method (DSM / Conventional upscaling)
• The method(s) used (e.g. Multiple linear regression, R
Kriging, Random Forest...);
• Map quality measures (Digital Soil Mapping)
• Mean error (ME), Mean absolute error (MAE), root mean
squared error (RMSE), amount of variance explained (R2);
• Units (tonnes/ha, kg/m2);
• Resampling Method (if used)

7. Metadata content - contacts
• Submitter contact details;
• Institute (Data Holder / Handler);
• Citation;
• Update Frequency;
• Comments, Remarks

8. Countries’ reports: different
cases
• Previously published scientific reports
• Technical reports prepared for GSOC
• Basic overviews of the mapping activities

9. Published/ scientifically
reviewed reports

10. Technical reports for GSOC

11. Basic overviews

12. Density of sampling points
Total number of profiles/sampling locations used by countries to
create the global map is: 929 042.
Density of point data (per country):

13. Sampling period
timeframe countries
before 1990 24
before and
after 1990
45
after 1990 48 Metadata
table
fragment:

14. Type of sampling
Metadata
table
fragment:

15. Georeferencing accuracy
Metadata
table
fragment:

16. SOC analysis methods
Metadata
table
fragment:

17. Bulk density analysis methods
Metadata
table
fragment:

18. Coarse fragments methods
Data on coarse
fragments is not
available in
many countries

19. Upscaling methods
Metadata
table
fragment:

20. Upscaling methods
• Conventional Upscaling: Geo-matching, Class-matching;
• Digital Soil Mapping methods: Multiple linear regression,
Regression Kriging, Multivariate adaptive regression splines,
Generalized Linear Models, Generalized Additive Models, etc.
• Machine learning techniques: Random Forest, Support
Vector Machine, Neural Networks, Regression trees,
Bayesian trees, etc.
• Ensemble models combining different DSM methods;
• Geostatistical methods: Ordinary Kriging, IDW.

21. Common features from the
reports and comments
• Biggest challenges:
• data collection;
• consolidating data from different sources;
• new mapping methods;
• uncertainty assessment;
• Many countries plan to update their map next year, some
plan to update on regular basis.

22. Thank you
for your attention!