ICOADS Web information page (Tuesday, 07-Jan-2014 23:57:59 UTC):

Figure 3a

Figure 3b

Figure 3. Upper panel: Close-up of 1° LNDLMT (green for land and white for ocean) and 2° LLN2F1 values (0 = ocean, 1 = land, 2 = coastal) for North America. Lower panel: Differences between LLN2F1 and a 2° file landmask, LNDLMT(2), reconstructed from LNDLMT without editing (differences are confined to North America). Yellow (pink) shows 2° boxes modified in LLN2F1 to become land (coast).

[Links to detailed][Landmask files]

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Updated: Jan 7, 2014 23:57:59 UTC
http://icoads.noaa.gov/mask_fig3.html