Jrshrenkはしばらくの間Rとパッケージを更新していないようです。理論的にはR、GGMAP、PNG、およびGGPLOT2のバージョンは十分と思われます。
Package: ggmap
Version: 2.4
Depends: R (>= 2.14.0), ggplot2 (>= 0.9.2)
Imports: proto, scales, RgoogleMaps, png, plyr, reshape2, grid, rjson,
mapproj, jpeg, geosphere, digest
Suggests: MASS, stringr
License: GPL-2
NeedsCompilation: no
Package: png
Version: 0.1-7
Depends: R (>= 2.9.0)
License: GPL-2 | GPL-3
NeedsCompilation: yes
Rとパッケージを更新して、問題を解決するかどうかを確認しようとします。
#Save your current packages but not the base ones:
savepackages <- rownames(installed.packages(priority='NA'))
write(savepackages, file="listpackages.txt")
#Check for Updates of R
library(installr)
check.for.updates.R(notify_user = TRUE, use_GUI = TRUE,
page_with_download_url = "http://cran.rstudio.com/bin/windows/base/",
pat = "R-[0-9.]+-win")
#Download and Install New Version
install.R(page_with_download_url = "http://cran.rstudio.com/bin/windows/base/",
pat = "R-[0-9.]+-win.exe", to_checkMD5sums = TRUE,
keep_install_file = TRUE, download_dir = tempdir(), silent = FALSE)
#Then reinstall packages
pkg.ls <- read.table("listpackages.txt")
install.packages(pkg.ls)