r - ggvis 中带有 layer_paths 的 R 的工具提示

Question

我对 ggvis 中的工具提示功能在我的等值线图上遇到了麻烦。我在下面附上了我的代码。代码运行良好，没有工具提示功能。但是，如果我添加工具提示，则只剩下新泽西州的土地(见图)。其他州都不见了。任何人都可以帮忙看看，我该如何修复它以通过添加工具提示功能恢复其他部分？非常感谢!

###my data for example
mapdata<-data.frame(
  state=c("alabama","alaska","arizona","arkansas","california","colorado","connecticut","delaware","florida","georgia","hawaii","idaho","illinois","indiana","iowa","kansas","kentucky","louisiana","maine","maryland","massachusetts","michigan", "minnesota","mississippi","missouri","montana","nebraska","nevada","new hampshire","new jersey","new mexico","new york","north carolina","north dakota","ohio","oklahoma", "oregon","pennsylvania","rhode island","south carolina","south dakota","tennessee","texas","utah","vermont","virginia","washington","west virginia","wisconsin","wyoming"),
  revenue=runif(50,min=100,max=9000))

library(rgdal)   
library(ggplot2) 
library(ggvis)

url   <- "http://www2.census.gov/geo/tiger/GENZ2014/shp/cb_2014_us_state_20m.zip"
tf    <- tempfile()
td    <- tempdir()
download.file(url,tf, mode="wb")  
unzip(tf, exdir=td)                

usa <- readOGR(dsn=td, layer="cb_2014_us_state_20m")
shp <- usa[(!usa$STUSPS %in% c("AK","HI")),] 

df<- fortify(shp)                    
df<- merge(df,cbind(id=rownames(shp@data),shp@data),by="id")   
df$state <- tolower(df$NAME)                                                  
df<- merge(df,mapdata,by="state")  
df<- df[order(df$order),]       

####function for tooltip
gg<-df
gg$id<-1:nrow(gg)
values<-function(x){
  if(is.null(x)) return(NULL)
  row<-gg[gg$id==x$id,]
  paste0("State: ",row$state,"<br />",
         "Revenue: ", row$revenue, "<br />")
}
####ggvis choropleth
gg %>%
  group_by(group) %>%
  ggvis(~long, ~lat, key:=~id)  %>%
  hide_axis("x") %>% 
  hide_axis("y")%>%
  add_tooltip(values,"hover")%>%
  layer_paths(fill= ~revenue)

Answer 1

我环顾四周，意识到由于路径是由来自数据集多行的信息构成的，因此像我们通常使用 那样尝试为工具提示使用唯一的行 ID 没有意义键。

然后我看到了这个very nice ggvis tutorial ，前进的道路对我来说变得更加清晰。您需要将工具提示基于您的分组 变量，然后以某种方式将该组中的许多行的信息筛选为单个值。在其他选项中，您可以通过仅从组中拉出第一行或在制作您的工具提示函数时仅使用 unique 值来执行此操作。

下面是我的意思的示例，使用您在 group_by 中使用的变量 group 来提取相关信息。

首先，使用 head 获取第一行:

values = function(x){
    if(is.null(x)) return(NULL)
    row = head(gg[gg$group == unique(x$group), ], 1)
    paste0("State: ", row$state,"<br />",
           "Revenue: ", row$revenue, "<br />")
}

或者，只需提取要显示的变量的 unique 值(每个状态/组有一个)。这在您的情况下可以正常工作，因为您只显示两个值:

values2 = function(x){
    if(is.null(x)) return(NULL)
    row = gg[gg$group == unique(x$group), ]
    paste0("State: ", unique(row$state),"<br />",
           "Revenue: ", unique(row$revenue), "<br />")
}

现在从 ggvis 中取出 key 参数并使用其中一个新的工具提示功能。现在交互式图表似乎工作正常。

gg %>%
    group_by(group) %>%
    ggvis(~long, ~lat)  %>%
    hide_axis("x") %>% 
    hide_axis("y")%>%
    add_tooltip(values, "hover")%>%
    layer_paths(fill= ~revenue)