Error(s) in re-building vignettes:
--- re-building ‘demo.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: maps
The 7-zip program is needed to unpack NHD downloads (http://www.7-zip.org/).
old-style crs object detected; please recreate object with a recent sf::st_crs()
old-style crs object detected; please recreate object with a recent sf::st_crs()
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
Warning in doTryCatch(return(expr), name, parentenv, handler) :
  no font could be found for family "Arial"
--- finished re-building ‘demo.Rmd’

--- re-building ‘flow.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: maps
The 7-zip program is needed to unpack NHD downloads (http://www.7-zip.org/).

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 3.9.1, GDAL 3.2.3, PROJ 7.2.1
Quitting from lines 29-34 (flow.Rmd) 
Error: processing vignette 'flow.Rmd' failed with diagnostics:
polygon edge not found
--- failed re-building ‘flow.Rmd’

--- re-building ‘network.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: maps
The 7-zip program is needed to unpack NHD downloads (http://www.7-zip.org/).

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 3.9.1, GDAL 3.2.3, PROJ 7.2.1
Warning in st_centroid.sf(mendota_lake) :
  st_centroid assumes attributes are constant over geometries of x
Quitting from lines 54-58 (network.Rmd) 
Error: processing vignette 'network.Rmd' failed with diagnostics:
polygon edge not found
--- failed re-building ‘network.Rmd’

SUMMARY: processing the following files failed:
  ‘flow.Rmd’ ‘network.Rmd’

Error: Vignette re-building failed.
Execution halted