標籤與素食主義者的位置:: ordispider

Question

我使用素食主義者進行DCA協調。我想展示我的分組網站，但是當我使用ordispider時，組的標籤隱藏了彼此。我怎樣才能調整自己的位置？是否有可能使用orditkplot莫名其妙？

Answer 1

不，這是不可能的orditkplot()與ordispider()，它根本不知道如何處理這樣的任意繪圖功能。

您不指示爲什麼要使用ordispider()在DCA排序中顯示您的分組網站？您不需要將它們加入某個質心或類似組中即可指示組成員資格。相反，您可以使用繪圖符號來區分組，例如

require("vegan") 
data(dune) 
data(dune.env) 

mod <- decorana(dune) 

plot(mod, display = "sites", type = "n") 

## colour & shape according to Management 
col <- c("red","orange","forestgreen","navy") 
pch <- 1:4 
## add the points 
with(dune.env, 
    points(mod, display = "sites", col = col[Management], 
      pch = pch[Management])) 
## add a legend 
legend("topright", 
     legend = with(dune.env, levels(Management)), 
     col = col, pch = pch, title = "Management", 
     bty = "n") 

另外，我想你可以不帶標籤的情節和後來加入他們，也許用locator()識別的情節在其中放置標籤的透明區域，例如：

plot(mod, display = "sites", type = "p") 
with(dune.env, ordispider(mod, groups = Management, col = "red")) 
## select 4 locations 
coords <- locator(with(dune.env, length(levels(Management)))) 

## now you have to click on the plot where you want the labels 
## automagically finishes after you click the 4th label in this case 

## draw labels 
text(coords, labels = with(dune.env, levels(Management))) 

Answer 2

您是否從vegan vignette嘗試了以下方法？

2.1. Cluttered plots 
Ordination plots are often congested: there is a large number of sites and species, and it may be impossible to display all clearly. In particular, two or more species may have identical scores and are plotted over each other. Vegan does not have (yet?) automatic tools for clean plotting in these cases, but here some methods you can try: 
- Zoom into graph setting axis limits xlim and ylim. You must typically set both, because 
vegan will maintain equal aspect ratio of axes. 
- Use points and add labell only some points with identify command. 
- Use select argument in ordination text and points functions to only show the specied 
items. 
- Use ordilabel function that uses opaque background to the text: some text labels will 
be covered, but the uppermost are readable. 
- Use automatic orditorp function that uses text only if this can be done without overwriting 
previous labels, but points in other cases.