Filenames contain the date for which the ice chart is valid. From 1550 until 1965, the filename contains the date only, and from 1966 onwards the date is preceded by the prefix “ice”. The date format is “yyyymmdd”. For example, the file “18660422.shp” contains the ice chart for 22 April 1866 (left image below), while “ice20020103.shp” contains the ice chart for the 3 January 2002 (right image below).
“Quicklooks” for all ice charts are sorted by date and listed below. These files grouped by year in a zipped file. They are in “jpeg” format and should be viewable with any standard graphics software. File names contain the date in “yyyymmdd” format in the same manner as for the full chart, but with the extension “.jpg”.