多行的 r-mapview 图例名称

问题描述

我正在尝试创建一个多行的图例，如 this leaflet example 所示，但使用的是 mapview 包。

按照上面的例子，这些情况可以正常工作：

    library(leaflet)
    library(raster)
    library(mapview)
    
    p <- shapefile(system.file("external/lux.shp",package="raster"))
    
    pal <- colorNumeric(
      palette = "Reds",domain = p$AREA)
    
    p %>% 
      leaflet() %>% 
      addTiles() %>% 
      addpolygons(stroke=FALSE,color = ~pal(AREA),fillOpacity = 1) %>% 
      addLegend(pal = pal,values = ~AREA,title = "line 1 </br> line 2")
    
    p %>%
      mapview(
        zcol = 'AREA',stroke = FALSE,alpha = 1,layer.name = "line 1"
      )

但是，将 或
引入 mapview layer.name 会引入错误。

    p %>%
      mapview(
        zcol = 'AREA',layer.name = "line 1 </br> line 2"
      )
    #Error in validateScalarName(name) : 
    #  Invalid argument 'name' (must be a non-empty character string and contain no '/' or '\')
    #In addition: Warning message:
    #In file.create(to[okay]) :
    #  cannot create file 'C:/RTMP\Rtmp6rsB0P\file2a687e904718/line1</br>line2_layer.fgb',reason #'Invalid argument'

    p %>%
      mapview(
        zcol = 'AREA',layer.name = "line 1 <br> line 2"
      )
    #Error in normalizePath(path.expand(path),winslash,mustWork) : 
    #  path[1]="lib/line1<br>line2-0.0.1": The filename,directory name,or volume label Syntax is #incorrect
    #In addition: Warning messages:
    #1: In file.create(to[okay]) :
    #  cannot create file 'C:/RTMP\Rtmp6rsB0P\file2a6843ec14e6/line1<br>line2_layer.fgb',reason #'Invalid argument'
    #2: In dir.create(target_dir) :
    #  cannot create dir 'lib\line1<br>line2-0.0.1',reason 'Invalid argument'

sessionInfo() 下面

R version 4.0.3 (2020-10-10)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 10 x64 (build 19043)

Matrix products: default

locale:
[1] LC_COLLATE=English_United States.1252 
[2] LC_CTYPE=English_United States.1252   
[3] LC_MONETARY=English_United States.1252
[4] LC_NUMERIC=C                          
[5] LC_TIME=English_United States.1252    

attached base packages:
[1] stats     graphics  Grdevices datasets  utils    
[6] methods   base     

other attached packages:
[1] mapview_2.10.0  raster_3.1-5    sp_1.4-5       
[4] leaflet_2.0.4.1 shiny_1.6.0    

loaded via a namespace (and not attached):
 [1] Rcpp_1.0.4.6            lattice_0.20-41        
 [3] leaflet.providers_1.9.0 png_0.1-7              
 [5] class_7.3-17            ps_1.6.0               
 [7] assertthat_0.2.1        digest_0.6.25          
 [9] utf8_1.2.1              mime_0.9               
[11] R6_2.5.0                reprex_2.0.0           
[13] stats4_4.0.3            evaluate_0.14          
[15] e1071_1.7-3             highr_0.8              
[17] pillar_1.6.0            rlang_0.4.10           
[19] rstudioapi_0.13         miniui_0.1.1.1         
[21] callr_3.7.0             jquerylib_0.1.4        
[23] rmarkdown_2.9           rgdal_1.5-23           
[25] webshot_0.5.2           htmlwidgets_1.5.1      
[27] munsell_0.5.0           compiler_4.0.3         
[29] httpuv_1.6.1            xfun_0.24              
[31] pkgconfig_2.0.3         base64enc_0.1-3        
[33] clipr_0.7.0             htmltools_0.5.1.1      
[35] tidyselect_1.1.0        tibble_3.1.1           
[37] codetools_0.2-16        fansi_0.4.2            
[39] dplyr_1.0.5             Crayon_1.4.1           
[41] withr_2.4.2             later_1.0.0            
[43] sf_0.9-8                grid_4.0.3             
[45] jsonlite_1.6.1          satellite_1.0.2        
[47] xtable_1.8-4            lifecycle_1.0.0        
[49] DBI_1.1.1               magrittr_2.0.1         
[51] units_0.6-6             scales_1.1.0           
[53] KernSmooth_2.23-17      cli_2.4.0              
[55] cachem_1.0.5            farver_2.0.3           
[57] renv_0.13.2             fs_1.5.0               
[59] promises_1.1.0          bslib_0.2.5.1          
[61] generics_0.0.2          ellipsis_0.3.1         
[63] vctrs_0.3.7             RColorBrewer_1.1-2     
[65] tools_4.0.3             leafem_0.1.3           
[67] glue_1.4.2              purrr_0.3.4            
[69] crosstalk_1.1.0.1       processx_3.5.2         
[71] fastmap_1.1.0           yaml_2.2.1             
[73] colorspace_1.4-1        classInt_0.4-3         
[75] knitr_1.28              sass_0.4.0 

关于如何解决这个问题有什么建议吗？

解决方法

看起来这是一个与缓存 .Rproj.user 和 R 临时目录文件夹中的地图文件有关的问题；我删除了 .Rproj.user shared/notebooks 子文件夹的内容并清除了 tempdir() 中的 R 临时目录，在重新启动 RStudio 和 R 后，正确创建了地图图例。感谢 @iago 在评论中确认示例代码可在 Linux 上运行。