I'm using the Julia language.

I have plotted a coast map

using GMT

p1 = coast(
    region=[-138, -90, 45, 63.5],
    proj=(name=:eqdc, center=[-114, 54.25], parallels=[47, 61]),
    xaxis=(annot=10,),  # Longitude (EW) ticks every 10 degrees
    yaxis=(annot=5,),   # Latitude (NS) ticks every 5 degrees
    res=:full,
    borders=((type=1, pen=("thinner",)), (type=2, pen=("thinner",))),
    shore=:thinnest,
    show=true
)

normal coastline map with land the default white

Adding in the line land = "#565A5C", results in an image that has ghost gridlines that change depending on the level of resolution (res=:full vs res=:high).

the same coastline map with land now a gray with a fine grid

the same but a slightly less fine grid

How to omit these gray grid lines?

I'm using the Julia language.

I have plotted a coast map

using GMT

p1 = coast(
    region=[-138, -90, 45, 63.5],
    proj=(name=:eqdc, center=[-114, 54.25], parallels=[47, 61]),
    xaxis=(annot=10,),  # Longitude (EW) ticks every 10 degrees
    yaxis=(annot=5,),   # Latitude (NS) ticks every 5 degrees
    res=:full,
    borders=((type=1, pen=("thinner",)), (type=2, pen=("thinner",))),
    shore=:thinnest,
    show=true
)

normal coastline map with land the default white

Adding in the line land = "#565A5C", results in an image that has ghost gridlines that change depending on the level of resolution (res=:full vs res=:high).

the same coastline map with land now a gray with a fine grid

the same but a slightly less fine grid

How to omit these gray grid lines?

• julia
• julia-plots
• pygmt

1 Answer 1

A possible workaround: Instead of specifying a fill as a color, specify any fill pattern number (1 to 90) and use the same color for background and foreground color. For the example given, the fill could be land="P1+b#565A5C+f#565A5C",

using GMT

p1 = coast(
    region=[-138, -90, 45, 63.5],
    proj=(name=:eqdc, center=[-114, 54.25], parallels=[47, 61]),
    xaxis=(annot=10,),  # Longitude (EW) ticks every 10 degrees
    yaxis=(annot=5,),   # Latitude (NS) ticks every 5 degrees
    res=:full,
    borders=((type=1, pen=("thinner",)), (type=2, pen=("thinner",))),
    shore=:thinnest,
    land="P1+b#565A5C+f#565A5C",
    show=true
)

This might run about a factor of five more slowly, but it seems to work: no ghostly gray grid lines.