我对GIS分析和ggmap软件包是完全陌生的。我现在要使用ggmap进行地理编码，您需要ggmap github版本和google API密钥。我已经有了我的API密钥。我试图安装ggmap（gibhub），但失败了。
> devtools::install_github("dkahle/ggmap")
Downloading GitHub repo dkahle/ggmap@master
Error in length(file_list) > 0 : failed to create directory ‘.’
In addition: Warning messages:
1: In untar2(tarfile, files, list, exdir) :
skipping pax global extended headers
2: In dir.create(path, showWarnings = TRUE, recursive = TRUE, ...) :
'.' already exists
> library(ggmap)
Error in library(ggmap) : there is no package called ‘ggmap’
我卸载了ggmap，重新启动了R studio，多次重新安装了ggmap，但是这些都不起作用。我已经做了自己的研究来解决此问题，但找不到解决方案。我将不胜感激任何帮助！预先谢谢你！
> devtools::session_info()
- Session info ----------------------------------------------------------------------------------------------------
setting value
version R version 3.5.1 (2018-07-02)
os Windows 7 x64 SP 1
system x86_64, mingw32
ui RStudio
language (EN)
collate English_United States.1252
ctype English_United States.1252
tz America/New_York
date 2019-01-24
- Packages --------------------------------------------------------------------------------------------------------
package * version date lib source
assertthat 0.2.0 2017-04-11 [1] CRAN (R 3.5.1)
backports 1.1.3 2018-12-14 [1] CRAN (R 3.5.2)
callr 3.1.1 2018-12-21 [1] CRAN (R 3.5.2)
cli 1.0.1 2018-09-25 [1] CRAN (R 3.5.1)
crayon 1.3.4 2017-09-16 [1] CRAN (R 3.5.1)
desc 1.2.0 2018-05-01 [1] CRAN (R 3.5.2)
devtools 2.0.1 2018-10-26 [1] CRAN (R 3.5.2)
digest 0.6.18 2018-10-10 [1] CRAN (R 3.5.1)
fs 1.2.6 2018-08-23 [1] CRAN (R 3.5.2)
glue 1.3.0 2018-07-17 [1] CRAN (R 3.5.1)
lattice 0.20-35 2017-03-25 [1] CRAN (R 3.5.1)
magrittr 1.5 2014-11-22 [1] CRAN (R 3.5.1)
memoise 1.1.0 2017-04-21 [1] CRAN (R 3.5.1)
pkgbuild 1.0.2 2018-10-16 [1] CRAN (R 3.5.2)
pkgload 1.0.2 2018-10-29 [1] CRAN (R 3.5.2)
prettyunits 1.0.2 2015-07-13 [1] CRAN (R 3.5.2)
processx 3.2.1 2018-12-05 [1] CRAN (R 3.5.2)
ps 1.3.0 2018-12-21 [1] CRAN (R 3.5.2)
R6 2.3.0 2018-10-04 [1] CRAN (R 3.5.1)
Rcpp 0.12.19 2018-10-01 [1] CRAN (R 3.5.1)
remotes 2.0.2 2018-10-30 [1] CRAN (R 3.5.2)
rlang 0.3.1 2019-01-08 [1] CRAN (R 3.5.2)
rprojroot 1.3-2 2018-01-03 [1] CRAN (R 3.5.2)
rstudioapi 0.9.0 2019-01-09 [1] CRAN (R 3.5.2)
sessioninfo 1.1.1 2018-11-05 [1] CRAN (R 3.5.2)
sp * 1.3-1 2018-06-05 [1] CRAN (R 3.5.2)
usethis 1.4.0 2018-08-14 [1] CRAN (R 3.5.2)
withr 2.1.2 2018-03-15 [1] CRAN (R 3.5.1)