Error(s) in re-building vignettes:
--- re-building ‘pct-international.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) and/or pandoc-citeproc not available. Falling back to R Markdown v1.
Warning in st_centroid.sf(zones) :
  st_centroid assumes attributes are constant over geometries of x
Warning in st_centroid.sfc(st_geometry(x), of_largest_polygon = of_largest_polygon) :
  st_centroid does not give correct centroids for longitude/latitude data
Quitting from lines 109-116 (pct-international.Rmd) 
Error: processing vignette 'pct-international.Rmd' failed with diagnostics:
cannot open the connection
--- failed re-building ‘pct-international.Rmd’

--- re-building ‘pct.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) and/or pandoc-citeproc not available. Falling back to R Markdown v1.
Quitting from lines 169-175 (pct.Rmd) 
Error: processing vignette 'pct.Rmd' failed with diagnostics:
cannot open the connection
--- failed re-building ‘pct.Rmd’

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

Attaching package: 'dplyr'

The following objects are masked from 'package:stats':

    filter, lag

The following objects are masked from 'package:base':

    intersect, setdiff, setequal, union

trying URL 'https://github.com/npct/pct-outputs-regional-R/raw/master/commute/msoa/isle-of-wight/z.Rds'
Content type 'application/octet-stream' length 14913 bytes (14 KB)
==================================================
downloaded 14 KB

trying URL 'https://github.com/npct/pct-outputs-regional-R/raw/master/commute/msoa/isle-of-wight/l.Rds'
Content type 'application/octet-stream' length 42595 bytes (41 KB)
==================================================
downloaded 41 KB

tmap mode set to interactive viewing
Linking to GEOS 3.6.1, GDAL 2.1.3, PROJ 4.9.3
Legend for line widths not available in view mode.
PhantomJS not found. You can install it with webshot::install_phantomjs(). If it is installed, please make sure the phantomjs executable can be found via the PATH variable.
Quitting from lines 113-133 (pct_training.Rmd) 
Error: processing vignette 'pct_training.Rmd' failed with diagnostics:
cannot open the connection
--- failed re-building ‘pct_training.Rmd’

SUMMARY: processing the following files failed:
  ‘pct-international.Rmd’ ‘pct.Rmd’ ‘pct_training.Rmd’

Error: Vignette re-building failed.
Execution halted