r - ggplot2 中两种美学和 geom_abline 的图例

Question

我正在尝试为以下情节准备图例，虚线后跟 A，虚线后跟 B。它显示不正确。由于我有 2 个审美，它有时只显示一种线型，有时什么都不显示。我使用了 scale_linetype_manual() 和 guides()，但是它无法产生预期的效果。但是

我创建的代码，我删除了显示我尝试制作图例的代码。

exemplo<-data.frame(Location = c("Tiburon Peninsula", "San Francisco","Santa Barbara area", "Santa Monica Mountains", "Marin County", 
                             "Santa Cruz Mountains", "Monterey County", "San Diego County","California Coast"),
                Area = c(5.9, 45, 110, 320, 529, 1386, 3324,4260, 24520),
                Species = c(370L, 640L, 680L, 640L, 1060L, 1200L,1400L, 1450L, 2525L))
modelo<-lm(log(Species,10)~log(Area,10),data=exemplo)

modelo_nls<-nls(Species~a*Area^z,start=list(a=1,z=0.25),data=exemplo)
linha<-data.frame(x=log10(seq(1,25000,100)),y=log10(predict(modelo_nls,newdata=data.frame(Area=seq(1,25000,100)))))
ggplot(data=exemplo,aes(x=log10(Area),y=log10(Species)) )  + geom_point() +
geom_abline(intercept = modelo$coefficients[1], slope = modelo$coefficients[2],linetype="dotted") +
geom_line(data=linha,aes(x=x,y=y),linetype="dashed")+        
xlab(label="Área(ha)") + ylab(label="Número de espécies")

Answer 1

一种方法是将您的两条预测线组合成一个数据框，并用一个额外的列指示每行属于哪个模型。

# Add model = 'A' to this data frame (I may have got A and B the wrong way round)
   linha <- data.frame(x = log10(seq(1,25000,100)),
                       y = log10(predict(modelo_nls,newdata=data.frame(Area=seq(1,25000,100)))),
                       model = 'A')

# Make data frame of line from modelo
lin2 <- data.frame(x = log10(seq(1,25000,100)), 
                   y = predict(modelo, newdata = list(Area = seq(1,25000,100))), 
                   model = 'B')

# Combine two models
combinedLines <- rbind(linha, lin2)

然后以模型为美学进行绘图

ggplot(data=exemplo,aes(x=log10(Area),y=log10(Species)) )  + geom_point() +
geom_line(data=combinedLines, aes(x=x,y=y, linetype = model))+        
xlab(label="Área(ha)") + ylab(label="Número de espécies")