Error(s) in re-building vignettes:
  ...
--- re-building ‘GADMTools_GRAPHICS.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) not available. Falling back to R Markdown v1.
Loading required package: sp
Loading required package: classInt
Loading required package: sf
Linking to GEOS 3.6.4, GDAL 2.2.4, PROJ 5.2.0
Loading required package: rgdal
rgdal: version: 1.5-23, (SVN revision 1121)
Geospatial Data Abstraction Library extensions to R successfully loaded
Loaded GDAL runtime: GDAL 2.2.4, released 2018/03/19
Path to GDAL shared files: /usr/local/share/gdal
GDAL binary built with GEOS: TRUE 
Loaded PROJ runtime: Rel. 5.2.0, September 15th, 2018, [PJ_VERSION: 520]
Path to PROJ shared files: (autodetected)
Linking to sp version:1.4-5

Attaching package: 'GADMTools'

The following object is masked from 'package:utils':

    vignette

Joining, by = "NAME_4"
--- finished re-building ‘GADMTools_GRAPHICS.Rmd’

--- re-building ‘GADMTools_ISO_3166-1_alpha-3.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) not available. Falling back to R Markdown v1.
Loading required package: sp
Loading required package: classInt
Loading required package: sf
Linking to GEOS 3.6.4, GDAL 2.2.4, PROJ 5.2.0
Loading required package: rgdal
rgdal: version: 1.5-23, (SVN revision 1121)
Geospatial Data Abstraction Library extensions to R successfully loaded
Loaded GDAL runtime: GDAL 2.2.4, released 2018/03/19
Path to GDAL shared files: /usr/local/share/gdal
GDAL binary built with GEOS: TRUE 
Loaded PROJ runtime: Rel. 5.2.0, September 15th, 2018, [PJ_VERSION: 520]
Path to PROJ shared files: (autodetected)
Linking to sp version:1.4-5

Attaching package: 'GADMTools'

The following object is masked from 'package:utils':

    vignette

Quitting from lines 19-27 (GADMTools_ISO_3166-1_alpha-3.Rmd) 
Error: processing vignette 'GADMTools_ISO_3166-1_alpha-3.Rmd' failed with diagnostics:
NA/NaN argument
--- failed re-building ‘GADMTools_ISO_3166-1_alpha-3.Rmd’

--- re-building ‘GADMTools_Manipulating_Shapefiles.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) not available. Falling back to R Markdown v1.
Loading required package: sp
Loading required package: classInt
Loading required package: sf
Linking to GEOS 3.6.4, GDAL 2.2.4, PROJ 5.2.0
Loading required package: rgdal
rgdal: version: 1.5-23, (SVN revision 1121)
Geospatial Data Abstraction Library extensions to R successfully loaded
Loaded GDAL runtime: GDAL 2.2.4, released 2018/03/19
Path to GDAL shared files: /usr/local/share/gdal
GDAL binary built with GEOS: TRUE 
Loaded PROJ runtime: Rel. 5.2.0, September 15th, 2018, [PJ_VERSION: 520]
Path to PROJ shared files: (autodetected)
Linking to sp version:1.4-5

Attaching package: 'GADMTools'

The following object is masked from 'package:utils':

    vignette

Warning: attribute variables are assumed to be spatially constant throughout all geometries
--- finished re-building ‘GADMTools_Manipulating_Shapefiles.Rmd’

SUMMARY: processing the following file failed:
  ‘GADMTools_ISO_3166-1_alpha-3.Rmd’

Error: Vignette re-building failed.
Execution halted