Error(s) in re-building vignettes:
--- re-building ‘v1.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) not available. Falling back to R Markdown v1.
--- finished re-building ‘v1.Rmd’

--- re-building ‘v2.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) not available. Falling back to R Markdown v1.
--- finished re-building ‘v2.Rmd’

--- re-building ‘v3.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) not available. Falling back to R Markdown v1.
Quitting from lines 34-36 (v3.Rmd) 
Error: processing vignette 'v3.Rmd' failed with diagnostics:
polygon edge not found
--- failed re-building ‘v3.Rmd’

--- re-building ‘v4.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) not available. Falling back to R Markdown v1.
--- finished re-building ‘v4.Rmd’

--- re-building ‘v5.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) not available. Falling back to R Markdown v1.
--- finished re-building ‘v5.Rmd’

--- re-building ‘v6.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) not available. Falling back to R Markdown v1.
--- finished re-building ‘v6.Rmd’

--- re-building ‘v7.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) not available. Falling back to R Markdown v1.
--- finished re-building ‘v7.Rmd’

--- re-building ‘v8.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) not available. Falling back to R Markdown v1.
Quitting from lines 57-58 (v8.Rmd) 
Error: processing vignette 'v8.Rmd' failed with diagnostics:
polygon edge not found
--- failed re-building ‘v8.Rmd’

--- re-building ‘v9.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) not available. Falling back to R Markdown v1.
Quitting from lines 27-31 (v9.Rmd) 
Error: processing vignette 'v9.Rmd' failed with diagnostics:
polygon edge not found
--- failed re-building ‘v9.Rmd’

SUMMARY: processing the following files failed:
  ‘v3.Rmd’ ‘v8.Rmd’ ‘v9.Rmd’

Error: Vignette re-building failed.
Execution halted