USDA Textural Classification Data
This dataset was issued by the United States Department of Agriculture (USDA) in the form of a ternary diagram, this original ternary diagram has been converted to numerical data and included here.
data(USDA)
1row per point, many points per classification representing the extremes of the area.
United States Department of Agriculture (USDA)
Nicholas Hamilton
Soil Mechanics Level 1, Module 3, USDA Textural Classification Study Guide
#Load the Libraries
library(ggtern)
library(plyr)
#Load the Data.
data(USDA)
#Put tile labels at the midpoint of each tile.
USDA.LAB <- ddply(USDA,"Label",function(df){
apply(df[,1:3],2,mean)
})
#Tweak
USDA.LAB$Angle = sapply(as.character(USDA.LAB$Label),function(x){
switch(x,"Loamy Sand"=-35,0)
})
#Construct the plot.
ggtern(data=USDA,aes(Sand,Clay,Silt,color=Label,fill=Label)) +
geom_polygon(alpha=0.75,size=0.5,color="black") +
geom_mask() +
geom_text(data=USDA.LAB,aes(label=Label,angle=Angle),color="black",size=3.5) +
theme_rgbw() +
theme_showsecondary() +
theme_showarrows() +
weight_percent() +
guides(fill='none') +
theme_legend_position("topleft") +
labs(title = "USDA Textural Classification Chart",
fill = "Textural Class",
color = "Textural Class")Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.