Error(s) in re-building vignettes:
  ...
--- re-building ‘intro.Rmd’ using rmarkdown
** Processing: /home/hornik/tmp/R.check/r-devel-gcc/Work/PKGS/distanceto.Rcheck/vign_test/distanceto/vignettes/intro_files/figure-html/unnamed-chunk-2-1.png
288x288 pixels, 8 bits/pixel, 255 colors in palette
Reducing image to 8 bits/pixel, grayscale
Input IDAT size = 4166 bytes
Input file size = 5021 bytes

Trying:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 3736
  zc = 9  zm = 8  zs = 1  f = 0		IDAT size = 3732
  zc = 1  zm = 8  zs = 2  f = 0
  zc = 9  zm = 8  zs = 3  f = 0
  zc = 9  zm = 8  zs = 0  f = 5
  zc = 9  zm = 8  zs = 1  f = 5
  zc = 1  zm = 8  zs = 2  f = 5
  zc = 9  zm = 8  zs = 3  f = 5
                               
Selecting parameters:
  zc = 9  zm = 8  zs = 1  f = 0		IDAT size = 3732

Output IDAT size = 3732 bytes (434 bytes decrease)
Output file size = 3810 bytes (1211 bytes = 24.12% decrease)

** Processing: /home/hornik/tmp/R.check/r-devel-gcc/Work/PKGS/distanceto.Rcheck/vign_test/distanceto/vignettes/intro_files/figure-html/unnamed-chunk-3-1.png
288x288 pixels, 8 bits/pixel, 256 colors in palette
Reducing image to 8 bits/pixel, grayscale
Input IDAT size = 4619 bytes
Input file size = 5477 bytes

Trying:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 4163
  zc = 9  zm = 8  zs = 1  f = 0		IDAT size = 4156
  zc = 1  zm = 8  zs = 2  f = 0
  zc = 9  zm = 8  zs = 3  f = 0
  zc = 9  zm = 8  zs = 0  f = 5
  zc = 9  zm = 8  zs = 1  f = 5
  zc = 1  zm = 8  zs = 2  f = 5
  zc = 9  zm = 8  zs = 3  f = 5
                               
Selecting parameters:
  zc = 9  zm = 8  zs = 1  f = 0		IDAT size = 4156

Output IDAT size = 4156 bytes (463 bytes decrease)
Output file size = 4234 bytes (1243 bytes = 22.69% decrease)


Quitting from lines 114-119 [unnamed-chunk-4] (intro.Rmd)
Error: processing vignette 'intro.Rmd' failed with diagnostics:
there is no package called 'raster'
--- failed re-building ‘intro.Rmd’

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

Error: Vignette re-building failed.
Execution halted