Yesterday in Why do I need two extra three byte values to make a 222x222 png using imagemagick (and why didn’t this surface in 2016? 64 bit boundary issue? Padding issue? Little Endian? Big Endian?) I was wrong. Not an imagemagick issue it turns out but a an unclean data problem; one of the rows is missing an average colour because there was no thumbnail in flickr. No thumbnail means nothing to compute the average colour of so the row is blank in the dataset! Fixed it by removing that one row using grep

Details

12april2021 figured it out, it’s my non clean data :-)

remove the one row i.e. row 19907 without a thumbnail and therefore without an average colour and then go from there!

grep  "#" 2020-and-2019-roland-flickr-imagemagick-average-colours.txt \
> missing-thumbnail-with-missing-avgcolour-removed-2020-and-2019-roland-flickr-imagemagick-average-colours.txt
head -n 49284 missing-thumbnail-with-missing-avgcolour-removed-2020-and-2019-roland-flickr-imagemagick-average-colours.txt \
>49284-missing-thumbnail-with-missing-avgcolour-removed-2020-and-2019-roland-flickr-imagemagick-average-colours.txt
xxd -l 49284 -u -r -p \
49284-missing-thumbnail-with-missing-avgcolour-removed-2020-and-2019-roland-flickr-imagemagick-average-colours.txt \
> 49284-missing-thumbnail-with-missing-avgcolour-removed-2020-and-2019-roland-flickr-imagemagick-average-colours.rgb
magick -depth 8 -size 222x222 \
49284-missing-thumbnail-with-missing-avgcolour-removed-2020-and-2019-roland-flickr-imagemagick-average-colours.rgb \
49284-missing-thumbnail-with-missing-avgcolour-removed-2020-and-2019-roland-flickr-imagemagick-average-colours.png

12april2021 probably not an imagemagick but a bug in my data aka i forgot that the average colour is missing for 1 row!

row 19907 doesn’t have an average colour because flickr doesn’t have a thumbnail!

% grep -C 3 -vn "#" 1st-49284-2020-2019-roland-flickr-average-colours.txt 
19904-#333436
19905-#AAABAD
19906-#AFAFAF
19907:
19908-#A7A9AA
19909-#B7B8B7
19910-#B5B6B6