我正在尝试在 ggplot2 中创建填充六边形(以六边形间隔晶格为中心的多边形)的镶嵌。我已经使用“plot”命令完成了此操作,但正在努力将其转换为 ggplot。
这是设置的代码:
# Generate a lattice of points equally spaced in the centers of a hexagonal lattice
dist = 1 # distance between the centers of hexagons
nx = dist*15 # horizontal extent
ny = dist*15 # vertical extent
MakeHexLattice = function(nx, ny, dist, origin=c(0,0)) {
locations = cbind(location = 1:(nx*ny),
x = sort(c(rep(seq(from=0, by=dist, length.out=nx),each=ceiling(ny/2)),
rep(seq(from=dist/2, by=dist, length.out=nx),
each=floor(ny/2)))) + origin[1],
y = rep(c(seq(from=0, by = dist*sqrt(3), length.out=ceiling(ny/2)),
seq(from=dist*sqrt(3)/2, by=dist*sqrt(3),
length.out=floor(ny/2))) + origin[2], times=nx))
class(locations) = c(class(locations), "lattice")
attr(locations, "gridsize") = dist
return(locations)
}
这是使用'plot'创建图像的代码,看起来非常好:
landscape = MakeHexLattice(nx=nx,ny=ny,dist=dist,origin=c(0,0))
# Plot hexagonal lattice as points
plot(x=landscape[,2],y=landscape[,3], pch=19, col="black", cex=0.5, asp=1/1)
# Separate x and y coordinates
lx = landscape[,2] # x-coordinates
ly = landscape[,3] # y-coordinates
# Plot hexagonal lattice as filled hexagons
hex.x = cbind(lx + 0, lx + 0.5, lx + 0.5, lx + 0, lx - 0.5, lx - 0.5)
hex.y = cbind(ly - 1/(sqrt(3)), ly - 1/(2*sqrt(3)), ly + 1/(2*sqrt(3)), ly + 1/(sqrt(3)), ly + 1/(2*sqrt(3)), ly - 1/(2*sqrt(3)))
hex.vectors = cbind(hex.x, hex.y)
for(i in 1:(length(hex.vectors)/12)){
polygon(x=hex.vectors[i,1:6], y=hex.vectors[i,7:12], angle = 120, border=NULL, col="wheat",
lty = par("lty"), fillOddEven = FALSE)
}
关于如何使用 ggplot2(我正在过渡到使用)完成同样的事情的任何提示?我曾尝试使用 geom_polygon,但似乎无法计算出 for 循环。 (另外,请不要告诉我使用“hexbin”——这不是我想要实现的目标!)
感谢您的帮助!
最佳答案
与 ggplot 中的大多数事情一样,绘图实际上非常简单,大部分工作是使您的数据具有正确的形状,以便它有意义。 for
循环完全没有必要,geom_polygon()
只需要一个带有 x 和 y 坐标的数据框,以及一个定义它们属于哪个组的变量。使用您的数据:
library(ggplot2)
library(reshape2)
#Get your coordinates in long format with an id
hexdat.x <- melt(cbind(id = 1:length(hex.x), as.data.frame(hex.x)), id.vars = "id", value.name = "x")
hexdat.y <- melt(cbind(id = 1:length(hex.y), as.data.frame(hex.y)), id.vars = "id", value.name = "y")
#Merge them into the same dataframe
hexdat <- merge(hexdat.x, hexdat.y)
head(hexdat)
# id variable x y
# 1 1 V1 0.0 -0.5773503
# 2 1 V2 0.5 -0.2886751
# 3 1 V3 0.5 0.2886751
# 4 1 V4 0.0 0.5773503
# 5 1 V5 -0.5 0.2886751
# 6 1 V6 -0.5 -0.2886751
现在要绘制六边形,您只需要为
ggplot
提供 x 和 y 坐标,并指定每个人所属的组:ggplot(hexdat, aes(x, y)) +
geom_polygon(aes(group = id), fill = "wheat", colour = "black")
关于r - 在 ggplot2 中绘制一系列填充六边形,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/24006361/