OBS:
In recent dev builds, areas of low lying land (tidal, or coastal areas) in the in game map and Eden editor map are covered by faint, partial yellow squares.
They are most obvious when map textures are disabled, but the are also displayed over the textured map.
In older builds, these areas were shaded light blue, but the shading was far more continuous, with intensity related to land height.
EXP:
Any shading of the map should be continuous, without any obvious tiling pattern.