afsp: Africa Soil Profiles Database
In GSIF: Global Soil Information Facilities

Description Usage Format Author(s) References Examples

A merge of the Africa Soil Profiles Database (AFSP) with 17,000+ geo-referenced legacy soil profile records, and AfSIS Sentinel Site database with 9000+ sampling locations.

1	data(afsp)

The afsp data set contains two data frames — sites and horizons. Sites table contains the following columns:

SOURCEID: factor; unique label to help a user identify a particular site (ProfileID in the AFSP)
SOURCEDB: factor; source data base
LONWGS84: numeric; longitude in decimal degrees on the WGS84 datum (X_LonDD in the AFSP)
LATWGS84: numeric; latitude in decimal degrees on the WGS84 datum (Y_LatDD in the AFSP)
TIMESTRR: character; the date on which this particular soil was described or sampled (T_Year in the AFSP)
TAXGWRB: factor; abbreviated soil group based on the WRB classification system (WRB06rg in the AFSP)
TAXNUSDA: factor; Keys to Soil Taxonomy taxon name e.g. "Plinthic Udoxic Dystropept" (USDA in the AFSP)
BDRICM: numeric; depth to bedrock in cm
DRAINFAO: factor; drainage class based on the FAO guidelines for soil description: E (excessively drained), S (somewhat excessively drained), W (well drained), M (moderately well drained), I (somewhat poorly drained) and V (very poorly drained)

Horizons table contains the following columns:

SOURCEID: factor; a short label to help a user identify a particular site
UHDICM: numeric; upper horizon depth from the surface in cm
LHDICM: numeric; lower horizon depth from the surface in cm
MCOMNS: factor; Munsell color moist
ORCDRC: numeric; soil organic carbon content in permilles
PHIHOX: numeric; pH index measured in water solution
SNDPPT: numeric; weight percentage of the sand particles (0.05–2 mm)
SLTPPT: numeric; weight percentage of the silt particles (0.0002–0.05 mm)
CLYPPT: numeric; weight percentage of the clay particles (<0.0002 mm)
CRFVOL: numeric; volume percentage of coarse fragments (> 2 mm)
BLD: numeric;bulk density in tonnes per cubic-meter
CEC: numeric; Cation exchange capacity (fine earth fraction) in cmolc/kg
NTO: numeric; total N content in permille or g/kg
EMGX: numeric; exchangable Mg in cmolc/kg

The Africa Soil Profiles Database have been prepared by Johan Leenaars <johan.leenaars@wur.nl>. This is a subset of the original database that can be downloaded via http://africasoils.net. The AfSIS Sentinel Site database is one of the main deliverables of the Africa Soil Information Service project.

Hengl, T., Heuvelink, G.B., Kempen, B., Leenaars, J.G., Walsh, M.G., Shepherd, K.D., Sila, A., MacMillan, R.A., de Jesus, J.M., Tamene, L. and Tondoh, J.E., (2015) Mapping soil properties of Africa at 250 m resolution: Random forests significantly improve current predictions. PloS one, 10(6), p.e0125814.
Leenaars, J.G.B. (2014) Africa Soil Profiles Database, Version 1.2. A compilation of geo-referenced and standardized legacy soil profile data for Sub Saharan Africa (with dataset). ISRIC report 2012/03. Africa Soil Information Service (AfSIS) project and ISRIC — World Soil Information, Wageningen, the Netherlands.
Africa Soil Information Service (http://africasoils.net)

## Not run: 
library(rgdal)
library(aqp)
library(sp)

data(afsp)
sites <- afsp$sites
coordinates(sites) <- ~ LONWGS84 + LATWGS84
proj4string(sites) <- "+proj=longlat +datum=WGS84"
## obtain country borders:
library(maps)
country.m = map('world', plot=FALSE, fill=TRUE)
IDs <- sapply(strsplit(country.m$names, ":"), function(x) x[1])
require(maptools)
country <- as(map2SpatialPolygons(country.m, IDs=IDs), "SpatialLines")
proj4string(country) = "+proj=longlat +datum=WGS84" 
## overlay and plot points and maps:
plot(country, col="darkgrey", xlim=c(-25.3,57.8), ylim=c(-34.8, 37.4))
points(sites, pch=21, bg="white", cex=.6, col="black")

## End(Not run)