Error(s) in re-building vignettes:
--- re-building 'cycling-potential-uk.Rmd' using rmarkdown
--- finished re-building 'cycling-potential-uk.Rmd'

--- re-building 'km-cycled.Rmd' using rmarkdown
Warning in CPL_read_ogr(dsn, layer, query, as.character(options), quiet,  :
  GDAL Error 1: SSL certificate problem: unable to get local issuer certificate
Quitting from lines 31-37 (km-cycled.Rmd) 
Error: processing vignette 'km-cycled.Rmd' failed with diagnostics:
Cannot open "https://github.com/npct/pct-outputs-regional-notR/raw/master/commute/lsoa/oxfordshire/rnet_full.geojson"; The file doesn't seem to exist.
--- failed re-building 'km-cycled.Rmd'

--- re-building 'pct-international.Rmd' using rmarkdown
--- finished re-building 'pct-international.Rmd'

--- re-building 'pct.Rmd' using rmarkdown
Linking to GEOS 3.6.2, GDAL 3.0.4, PROJ 7.0.0

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

Quitting from lines 115-117 (pct.Rmd) 
Error: processing vignette 'pct.Rmd' failed with diagnostics:
Cannot open "https://github.com/npct/pct-outputs-regional-notR/raw/master/commute/msoa/isle-of-wight/c.geojson"; The file doesn't seem to exist.
--- failed re-building 'pct.Rmd'

--- re-building 'pct_training.Rmd' using rmarkdown
Quitting from lines 237-242 (pct_training.Rmd) 
Error: processing vignette 'pct_training.Rmd' failed with diagnostics:
Cannot open "https://github.com/npct/pct-outputs-regional-notR/raw/master/commute/msoa/isle-of-wight/z.geojson"; The file doesn't seem to exist.
--- failed re-building 'pct_training.Rmd'

--- re-building 'uk-cities.Rmd' using rmarkdown

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

Linking to GEOS 3.6.2, GDAL 3.0.4, PROJ 7.0.0
Quitting from lines 45-47 (uk-cities.Rmd) 
Error: processing vignette 'uk-cities.Rmd' failed with diagnostics:
Cannot open "https://github.com/npct/pct-outputs-regional-notR/raw/master/commute/lsoa/wales/z.geojson"; The file doesn't seem to exist.
--- failed re-building 'uk-cities.Rmd'

SUMMARY: processing the following files failed:
  'km-cycled.Rmd' 'pct.Rmd' 'pct_training.Rmd' 'uk-cities.Rmd'

Error: Vignette re-building failed.
Execution halted