r - R Shiny 应用程序中的传单 map 图例不显示颜色

当我尝试将图例添加到包含在 Shiny 应用程序中的传单 map (使用 Leaflet for R 包)的传单 map 时，图例不显示调色板的颜色。相反，它只显示为 NA 值指定的颜色，在本例中为白色。

该应用程序执行以下操作:

首先，它根据用户输入过滤一组数据

然后它从过滤后的数据中生成一个等值线图

这是我用来制作图例的代码:

addLegend(position = "bottomleft",
   pal = pal, values = shp.data()$stat.selected,
   title = "Legend",
   opacity = .5)

其中 pal 是分位数调色板，如下所示

pal <-colorQuantile(c("#B2FF66","#66CC00","#4C9900","#336600","#193300"),
                    NULL, n = 5, na.color="#FFFFFF")

shp.data() 是一个响应式(Reactive)表达式，它是一个基于用户输入过滤的 shapefile，stat_selected 是用户选择用于映射到颜色的特定统计数据。

我收到以下警告:

Warning in is.na(x) :
  is.na() applied to non-(list or vector) of type 'NULL'
Warning in is.na(values) :
  is.na() applied to non-(list or vector) of type 'NULL'

我最初尝试按照 R 页面传单上的示例制作图例，并将参数 values = ~stat.selected 用于 addLegend 函数，但出现此错误:

Error in UseMethod("doResolveFormula") :
  no applicable method for 'doResolveFormula' applied to an object of class "NULL"

最佳答案

早些时候，我只有一个简单的片段，展示了如何添加图例。我没有在图例值之前使用 ~ 作为规范。我做了传统的 dataframe$column 并且效果很好。

现在已更新以查看它们如何组合在一起。这是在创建所有变量切割等之后的完整映射运行。最终清理的数据框称为 zipData

# create a full popup
# add some HTML for editing the styles

zipData$popUp <- paste('<strong>',zipData$Street, '</strong><br>',
                       'TIV = $',prettyNum(zipData$tiv, big.mark = ',',preserve.width = 'none'), '<br>',
                       'City: ', zipData$city, '<br>',
                       'YrBuilt = ', zipData$YearBuilt, '<br>',
                       'Construction = ', zipData$ConstructionCode, '<br>',
                       'Occupancy = ', zipData$OccupancyCode, '<br>',
                       'Premium = $' , prettyNum(zipData$Premium, big.mark = ',',preserve.width = 'none') , '<br>',
                       'GrossArea = ', prettyNum(zipData$GrossArea, big.mark = ',', preserve.width = 'none'), '<br>',
                       'RoofYr = ', zipData$RoofYearBuilt, '<br>')

# set color scale for key factor
colorsConst <- colorFactor(rainbow(4), zipData$ConstructionCode)

# color scales for numerical bins
colorstivValue <- colorFactor(palette = 'Accent', zipData$tivValueLvl)
colorsYrBuilt <- colorFactor(palette = 'Spectral', zipData$yrBuiltLvl)
colorsRoofYrBuilt <- colorFactor(palette = "YlOrRd", zipData$roofYrBuiltLvl)


# begin the leaflet map construction
# create the map opbject

m <- leaflet() %>%
    addTiles() %>%

# add different tiles for different color schemes

    addProviderTiles(providers$OpenStreetMap, group = 'Open SM')  %>%
    addProviderTiles(providers$Stamen.Toner, group = 'Toner')  %>%
    addProviderTiles(providers$CartoDB.Positron, group = 'CartoDB')  %>%
    addProviderTiles(providers$Esri.NatGeoWorldMap, group = 'NG World') %>%
    setView(lng = -90, lat = 30, zoom = 10) %>%

##############################

    # this section is for plotting the variables
    # each variable below is a layer in the map

    # construction
    addCircleMarkers(data = zipData, lat = ~Lat, lng = ~Lon,
                     color = ~colorsConst(ConstructionCode), popup = zipData$popUp,
                     radius = 5, group = 'Construction') %>%
    # tiv
    addCircleMarkers(data = zipData, lat = ~Lat, lng = ~Lon,
                     color = ~colorstivValue(tivLvl), popup = zipData$popUp,
                     radius = ~tiv/20000, group = 'Bldg Value') %>%

    # year built
    addCircleMarkers(data = zipData, lat = ~Lat, lng = ~Lon,
                     color = ~colorsYrBuilt(yrBuiltLvl), popup = zipData$popUp,
                     radius = ~YearBuilt/250, group = 'Yr Built') %>%


######################################

    # layer control

    addLayersControl(
        baseGroups = c('Open SM', 'Toner', 'Carto DB', 'NG World'),

        overlayGroups = c('Construction',
                          'TIV',
                          'Yr Built'
        ),
        options = layersControlOptions(collapsed = F)
    ) %>%


#################################################
add the legends for each of the variables


    # construction
    addLegend('bottomright', pal = colorsConst, values = zipData$ConstructionCode,
              title = 'Construction Code',
              opacity = 1) %>%

     # tiv
    addLegend('bottomleft', pal = colorstivValue, values = zipData$tivLvl,
              title = 'TIV',
              opacity = 1) %>%

    # year built
    addLegend('topleft', pal = colorsYrBuilt, values = zipData$yrBuiltLvl,
              title = 'Yr Built',
              opacity = 1)


m  # Print the map

map 的一部分如下所示。

关于r - R Shiny 应用程序中的传单 map 图例不显示颜色，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/30654397/