通过ggplot2中的多个点按月绘制箭头

Question

我的数据集很小

cent<-structure(list(temporal = structure(c(3L, 6L, 1L, 7L, 5L, 4L, 
2L), .Label = c("April", "August", "February", "July", "June", 
"March", "May"), class = "factor"), NMDS1 = c(0.0974540266588284, 
0.1688532488445, 0.0468643826727811, 0.0355451066297488, -0.0209516885503105, 
-0.206936981483144, -0.120828094772404), NMDS2 = c(-0.0101014005049961, 
0.030236007628167, -0.388205968271465, -0.166511878199233, -0.0172718994833608, 
0.321810567323985, 0.230044571506903)), row.names = c(3L, 6L, 
1L, 7L, 5L, 4L, 2L), class = "data.frame")

此数据表示每月nmds分析的质心位置。我想用ggplot绘制它（很简单）：

ggplot(cent, aes(x = NMDS1, y = NMDS2, colour = factor(temporal, levels = month.name))) +
  geom_line(arrow = arrow()) +# spiders
  geom_point(data = cent, size = 5) +                         
  geom_point() +                                              
  coord_fixed() + theme_classic()

但是我想画一条箭头连接所有点（按月顺序），以显示这些质心随时间的变化。我还无法弄清楚该怎么做，我将其放入MS paint中并在那里进行。任何帮助都会真正帮助您！

仅在某些情况下，我每月对昆虫进行抽样（每月10个相同的地点），并对数据进行非度量的多维标度分析。我根据数月计算了质心，并希望显示社区随着时间推移而发生的变化和变化。

Answer 1

library(ggplot2); library(dplyr)
ggplot(cent, aes(x = NMDS1, y = NMDS2, colour = factor(temporal, levels = month.name))) +
  geom_line(arrow = arrow()) +# spiders
  geom_point(data = cent, size = 5) +     
  geom_segment(aes(xend = lead(NMDS1), yend = lead(NMDS2)), 
               arrow = arrow(length = unit(0.05,"npc"), type = "closed")) +
  coord_fixed() + theme_classic()