title: ggmap's get_map returns 'Error in gzfile(file, "rb") : cannot open the connection'
body: <p>I have some R code to plot data on maps with ggmap. It was working fine last week. However, now when I run the line to get the map:</p>
  
  <pre><code>emap &lt;- get_map(c(-2.503704,43.18735),zoom=9,maptype="roadmap",color="bw")  
  </code></pre>
  
  <p>I get the following error:</p>
  
  <pre><code>Error in gzfile(file, "rb") : cannot open the connection
  In addition: Warning message:
  In gzfile(file, "rb") :
    cannot open compressed file '/var/folders/2w/2wSOAL2LFUC+2QkRaR1wI++++TI/-Tmp-//Rtmpj0TMx5/ggmap/index.rds', probable reason 'No such file or directory'
  </code></pre>
  
  <p>I have searched this forum and the web but can't find any other threads discussing this error.</p>
  
  <p>Any help is much appreciated.
  Regards,
  Noelia</p>
  
  <p>PS: sessionInfo() returns the following:</p>
  
  <pre><code>R version 3.1.2 (2014-10-31)
  Platform: x86_64-apple-darwin10.8.0 (64-bit)
  
  locale:
  [1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
  
  attached base packages:
  [1] stats     graphics  grDevices utils     datasets  methods   base     
  
  other attached packages:
  [1] mapproj_1.2-2  maps_2.3-9     ggmap_2.4      dplyr_0.4.1        xtable_1.7-4   ggplot2_1.0.1  reshape2_1.4.1
  
  loaded via a namespace (and not attached):
  [1] assertthat_0.1      colorspace_1.2-6    DBI_0.3.1           digest_0.6.8        geosphere_1.3-13    grid_3.1.2         
  [7] gtable_0.1.2        jpeg_0.1-8          labeling_0.3        lattice_0.20-31     lazyeval_0.1.10     magrittr_1.5       
  [13] MASS_7.3-40         munsell_0.4.2       parallel_3.1.2      plyr_1.8.1          png_0.1-7           proto_0.3-10       
  [19] Rcpp_0.11.5         RgoogleMaps_1.2.0.7 rjson_0.2.15        RJSONIO_1.3-0       scales_0.2.4        sp_1.0-17          
  [25] stringr_0.6.2       tools_3.1.2  
  </code></pre>