创建了一个生成三元(或更高维度)图的基本脚本。没有网格线或刻度线,但使用“基础”数组中的向量很容易添加这些功能。
from pylab import *
def ternaryPlot(
data,
# Scale data for ternary plot (i.e. a + b + c = 1)
scaling=True,
# Direction of first vertex.
start_angle=90,
# Orient labels perpendicular to vertices.
rotate_labels=True,
# Labels for vertices.
labels=('one','two','three'),
# Can accomodate more than 3 dimensions if desired.
sides=3,
# Offset for label from vertex (percent of distance from origin).
label_offset=0.10,
# Any matplotlib keyword args for plots.
edge_args={'color':'black','linewidth':2},
# Any matplotlib keyword args for figures.
fig_args = {'figsize':(8,8),'facecolor':'white','edgecolor':'white'},
):
'''
This will create a basic "ternary" plot (or quaternary, etc.)
'''
basis = array(
[
[
cos(2*_*pi/sides + start_angle*pi/180),
sin(2*_*pi/sides + start_angle*pi/180)
]
for _ in range(sides)
]
)
# If data is Nxsides, newdata is Nx2.
if scaling:
# Scales data for you.
newdata = dot((data.T / data.sum(-1)).T,basis)
else:
# Assumes data already sums to 1.
newdata = dot(data,basis)
fig = figure(**fig_args)
ax = fig.add_subplot(111)
for i,l in enumerate(labels):
if i >= sides:
break
x = basis[i,0]
y = basis[i,1]
if rotate_labels:
angle = 180*arctan(y/x)/pi + 90
if angle > 90 and angle <= 270:
angle = mod(angle + 180,360)
else:
angle = 0
ax.text(
x*(1 + label_offset),
y*(1 + label_offset),
l,
horizontalalignment='center',
verticalalignment='center',
rotation=angle
)
# Clear normal matplotlib axes graphics.
ax.set_xticks(())
ax.set_yticks(())
ax.set_frame_on(False)
# Plot border
ax.plot(
[basis[_,0] for _ in range(sides) + [0,]],
[basis[_,1] for _ in range(sides) + [0,]],
**edge_args
)
return newdata,ax
if __name__ == '__main__':
k = 0.5
s = 1000
data = vstack((
array([k,0,0]) + rand(s,3),
array([0,k,0]) + rand(s,3),
array([0,0,k]) + rand(s,3)
))
color = array([[1,0,0]]*s + [[0,1,0]]*s + [[0,0,1]]*s)
newdata,ax = ternaryPlot(data)
ax.scatter(
newdata[:,0],
newdata[:,1],
s=2,
alpha=0.5,
color=color
)
show()
R有一个名为VCD的外部包,应该可以满足您的需求。
文档非常好(与该包一起分发的122页手册);还有一本同名书籍,作者是该包的作者(Michael Friendly教授)。
要使用vcd创建三元图,只需调用ternaryplot()并传入一个m x 3矩阵,即一个具有三列的矩阵。
方法签名非常简单;仅需要一个参数(m x 3数据矩阵),所有关键字参数都与绘图的美学相关,除了scale,当设置为1时,按列归一化数据。
要在三元图上绘制数据点,给定点的坐标被计算为每个构成数据矩阵的特征值是单独的权重的质心点,因此点V(a,b,c)的坐标为
V(b, c/2, c * (3^.5)/2
install.packages(c("vcd"))
成功地将其安装在Fedora 12上。此外,来自ternaryplot
手册页面的示例非常好用。再次感谢!至于r
标签,我没有注意到您的评论,否则我会自己添加的。附言:我很高兴您喜欢攀岩之旅。 - Cristian Ciupitu使用以下代码生成:
# Load data
data(Feldspar)
# Sort it by decreasing pressure
# (so small grobs sit on top of large grobs
Feldspar <- Feldspar[with(Feldspar, order(-P.Gpa)), ]
# Build and Render the Plot
ggtern(data = Feldspar, aes(x = An, y = Ab, z = Or)) +
#the layer
geom_point(aes(fill = T.C,
size = P.Gpa,
shape = Feldspar)) +
#scales
scale_shape_manual(values = c(21, 24)) +
scale_size_continuous(range = c(2.5, 7.5)) +
scale_fill_gradient(low = "green", high = "red") +
#theme tweaks
theme_tern_bw() +
theme(legend.position = c(0, 1),
legend.justification = c(0, 1),
legend.box.just = "left") +
#tweak guides
guides(shape= guide_legend(order =1,
override.aes=list(size=5)),
size = guide_legend(order =2),
fill = guide_colourbar(order=3)) +
#labels and title
labs(size = "Pressure/GPa",
fill = "Temperature/C") +
ggtitle("Feldspar - Elkins and Grove 1990")
使用以下代码生成:
ggtern(data=Feldspar,aes(An,Ab,Or)) +
geom_confidence(aes(group=Feldspar,
fill=..level..,
alpha=1-..level..),
n=2000,
breaks=c(0.01,0.02,0.03,0.04,
seq(0.05,0.95,by=0.1),
0.99,0.995,0.9995),
color=NA,linetype=1) +
geom_density2d(aes(color=..level..)) +
geom_point(fill="white",aes(shape=Feldspar),size=5) +
theme_tern_bw() +
theme_tern_nogrid() +
theme(ternary.options=element_ternary(padding=0.2),
legend.position=c(0,1),
legend.justification=c(0,1),
legend.box.just="left") +
labs(color="Density",fill="Confidence",
title="Feldspar - Elkins and Grove 1990 + Confidence Levels + Density") +
scale_color_gradient(low="gray",high="magenta") +
scale_fill_gradient2(low="red",mid="orange",high="green",
midpoint=0.8) +
scale_shape_manual(values=c(21,24)) +
guides(shape= guide_legend(order =1,
override.aes=list(size=5)),
size = guide_legend(order =2),
fill = guide_colourbar(order=3),
color= guide_colourbar(order=4),
alpha= "none")
我刚刚发现了一个使用Python/Matplotlib生成三元图的工具,名为wxTernary。它可以通过http://wxternary.sourceforge.net/获取--我第一次尝试就成功地生成了一个三元图。
如果找不到更简单的方法,就找一个矢量绘图库来自己制作。
library(sos); findFn("{ternary plot}")
。 - Ben Bolker