更改文字/標籤ggplot圖例

Question

我相信這個問題與之前詢問的類似問題略有不同，因爲使用了scale_fill_brewer(。我工作在一個地區分佈與此類似https://gist.github.com/233134

，看起來像這樣：

而像傳說：

我喜歡它，但要將圖例上的標籤從切割外觀標籤（例如（2,4））更改爲更友好的內容，如'2％至4％'或'2％ - 4％'。我在其他地方看過它;很容易更改刻度__中的標籤，如here所示。我似乎無法弄清楚標籤=參數的放置位置。我當然可以重新編碼choropleth$rate_d，但這似乎是低效的。我應該在哪裏放置參數labels=c(A, B, C, D...)？

這裏是一塊感興趣的代碼（爲完整的代碼使用上面的鏈接）

choropleth$rate_d <- cut(choropleth$rate, breaks = c(seq(0, 10, by = 2), 35)) 

# Once you have the data in the right format, recreating the plot is straight 
# forward. 

ggplot(choropleth, aes(long, lat, group = group)) + 
    geom_polygon(aes(fill = rate_d), colour = alpha("white", 1/2), size = 0.2) + 
    geom_polygon(data = state_df, colour = "white", fill = NA) + 
    scale_fill_brewer(pal = "PuRd") 

預先感謝您的協助。

編輯：使用迪文的方法（應該已經張貼了這個錯誤，因爲這是我撞到前）

> ggplot(choropleth, aes(long, lat, group = group)) + 
+ geom_polygon(aes(fill = rate_d), colour = alpha("white", 1/2), size = 0.2) + 
+ geom_polygon(data = state_df, colour = "white", fill = NA) + 
+ scale_fill_brewer(pal = "PuRd", labels = lev4) 
Error: Labels can only be specified in conjunction with breaks 

Answer 1

除了增加水平的修改版本，你還需要設置scale_fill_brewer的「休息」參數：

lev = levels(rate_d) # used (2, 4] as test case 
lev2 <- gsub("\\,", "% to ", lev) 
lev3 <- gsub("\\]$", "%", lev2) 
lev3 
[1] "(2% to 4%" 
lev4 <- gsub("\\(|\\)", "", lev3) 
lev4 
[1] "2% to 4%" 

ggplot(choropleth, aes(long, lat, group = group)) + 
    geom_polygon(aes(fill = rate_d), colour = alpha("white", 1/2), size = 0.2) + 
    geom_polygon(data = state_df, colour = "white", fill = NA) + 
    scale_fill_brewer(pal = "PuRd", labels = lev4, , breaks=seq(0, 10, by = 2))