anchor.diff:  	
   RUN DEBIAN_FRONTEND=noninteractive wget \
      https://mirrors.nics.utk.edu/cran/src/contrib/sf_0.5-4.tar.gz \
  -   https://mirrors.nics.utk.edu/cran/src/contrib/tigris_0.5.3.tar.gz \
  -   https://mirrors.nics.utk.edu/cran/src/contrib/units_0.4-6.tar.gz \
      https://mirrors.nics.utk.edu/cran/src/contrib/rgdal_1.2-8.tar.gz \
      https://mirrors.nics.utk.edu/cran/src/contrib/rgeos_0.3-23.tar.gz \
      https://mirrors.nics.utk.edu/cran/src/contrib/maptools_0.9-2.tar.gz \
  
positive.code: RUN rm \
     sf_0.5-4.tar.gz \
     sp_1.2-5.tar.gz \
     units_0.4-6.tar.gz \
     rgdal_1.2-8.tar.gz \
     rgeos_0.3-23.tar.gz \
     maptools_0.9-2.tar.gz \
  
negative.code:  
   
  RUN DEBIAN_FRONTEND=noninteractive R CMD INSTALL \
     sf_0.5-4.tar.gz \
     sp_1.2-5.tar.gz  \
     rgdal_1.2-8.tar.gz \
  