r - 在 R 中使用 rsf（资源选择功能）时强制引入的 NA

Question

我到底做错了什么？我需要担心这些 NA 吗？

我正在使用 R 的 ResourceSelection 包中的 rsf 函数。下面是我的带有输出和警告消息的代码。

>

 ## Read CVS Files
> brood <- read.csv("GrouseBroodData2014.csv")
> randoms <- read.csv("Randoms.csv")
> all <- read.csv("2014Broods_AllData.csv")
> 
> #brood
> #randoms
> 
> #summary(brood)
> #summary(randoms)
> 
> #kdepairs (brood)
> #kdepairs (randoms)
> 
> 
> rsf(Pres~VOR+LD+MXHT+X.grass+X.forbs+X.sedges+X.rush+BG+Litter, all, m="Group" , B=100, model = TRUE)
  |++++++++++++++++++++++++++++++++++++++++++++++++++| 100%

Call:
rsf(formula = Pres ~ VOR + LD + MXHT + X.grass + X.forbs + X.sedges + X.rush + BG + Litter, data = all, m = "Group", 
    B = 100, model = TRUE)

Resource Selection Function (Exponential RSF) model
Matched Used-Available design
Maximum Likelihood estimates

Coefficients (log link):
     VOR        LD      MXHT   X.grass   X.forbs  X.sedges    X.rush        BG    Litter  
 -0.1945   -1.3590    0.1585   -0.3078   -0.3009   -0.2647    1.0375   -0.3502   -0.3487  

Warning message:
In rsf.fit(X = X, Y = Y, m = m, link = "log", B = B, inits = inits,  :
  NAs introduced by coercion