Description Usage Format Note Author(s) References See Also Examples
Probability density for texture triangle (USDA system) based on global soil profile data (see ISRIC WoSIS).
1 |
The USDA.TT.im
data frame contains the following columns:
v
numeric; probability density derived using the soiltexture::TT.kde2d
function and global soil profile data
TEXMHT
factor; USDA soil texture class estimated by hand (one of the following: "C"
, "SiC"
, "SC"
, "CL"
, "SiCL"
, "SCL"
, "L"
, "SiL"
, "SL"
, "Si"
, "LS"
, "S")
s1
numeric; horizontal coordinate (sand content 0–1) in the texture triangle system
s2
numeric; vertical coordinate (0–0.85) in the texture triangle system
Texture by hand class can be converted to sand, silt, clay content fractions by using the TT2tri
function. This function uses the v
column in the USDA.TT.im
(i.e. prior probability densities) to adjust for texture fraction combinations that are more probable.
Tomislav Hengl
Skaggs, T. H., Arya, L. M., Shouse, P. J., Mohanty, B. P., (2001) Estimating Particle-Size Distribution from Limited Soil Texture Data. Soil Science Society of America Journal 65 (4): 1038-1044.
FAO.SoilProfileCollection
, soil.dom
1 2 3 4 5 6 7 8 9 10 11 12 13 | ## plot prior probabilities:
library(sp)
data(USDA.TT.im)
gridded(USDA.TT.im) <- ~s1+s2
spplot(USDA.TT.im["v"])
## Not run: library(soiltexture)
## convert textures by hand to sand, silt and clay:
TEXMHT <- c("CL","C","SiL","SiL","missing")
x <- TT2tri(TEXMHT)
x
## End(Not run)
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