Error(s) in re-building vignettes:
  ...
--- re-building ‘bes-2015.Rmd’ using rmarkdown
--- finished re-building ‘bes-2015.Rmd’

--- re-building ‘bes-2017.Rmd’ using rmarkdown
--- finished re-building ‘bes-2017.Rmd’

--- re-building ‘census-11.Rmd’ using rmarkdown
--- finished re-building ‘census-11.Rmd’

--- re-building ‘introduction.Rmd’ using rmarkdown
Linking to GEOS 3.7.1, GDAL 2.4.0, PROJ 5.2.0

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

Downloading constituency data
Connecting to API
Retrieving page 1 of 7
Retrieving page 2 of 7
Retrieving page 3 of 7
Retrieving page 4 of 7
Retrieving page 5 of 7
Retrieving page 6 of 7
Retrieving page 7 of 7
Joining, by = c("pano", "ons_const_id", "constituency_name", "country", "region", "constituency_type")
`geom_smooth()` using method = 'loess' and formula 'y ~ x'
Warning: Removed 60 rows containing non-finite values (stat_smooth).
Warning: Removed 60 rows containing missing values (geom_point).
Quitting from lines 174-191 (introduction.Rmd) 
Error: processing vignette 'introduction.Rmd' failed with diagnostics:
VECTOR_ELT() can only be applied to a 'list', not a 'double'
--- failed re-building ‘introduction.Rmd’

--- re-building ‘mapping-local-authorities.Rmd’ using rmarkdown
Linking to GEOS 3.7.1, GDAL 2.4.0, PROJ 5.2.0

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

Joining, by = "name"
Warning: Column `majority_party`/`party_name` joining character vector and factor, coercing into character vector
--- finished re-building ‘mapping-local-authorities.Rmd’

--- re-building ‘using-cartograms.Rmd’ using rmarkdown
Linking to GEOS 3.7.1, GDAL 2.4.0, PROJ 5.2.0

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

Warning: Column `winner_17`/`party_name` joining factors with different levels, coercing to character vector

Please use cartogram_cont() instead of cartogram().

Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Mean size error for iteration 1: 1.84051824940637
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Mean size error for iteration 2: 1.57795616352671
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Mean size error for iteration 3: 1.38542765296568
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Mean size error for iteration 4: 1.24990590568916
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Mean size error for iteration 5: 1.15911005794951
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Mean size error for iteration 6: 1.10049759826218
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Mean size error for iteration 7: 1.06348707731059
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Mean size error for iteration 8: 1.04029321041635
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Mean size error for iteration 9: 1.02573148730624
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Mean size error for iteration 10: 1.01655498377918
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Mean size error for iteration 11: 1.01074124278594
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Mean size error for iteration 12: 1.00702644638021
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Mean size error for iteration 13: 1.00463696776579
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Mean size error for iteration 14: 1.00308488963412
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Warning in RGEOSMiscFunc(spgeom, byid, "rgeos_area") :
  Spatial object is not projected; GEOS expects planar coordinates
Mean size error for iteration 15: 1.0020731354118
--- finished re-building ‘using-cartograms.Rmd’

SUMMARY: processing the following file failed:
  ‘introduction.Rmd’

Error: Vignette re-building failed.
Execution halted