How to hide the grid lines using GRIDM function behind a marker in map axes?

When I use GRIDM for a map containing a marker, the grid lines appear in front of the marker.

axesm('pcarree','MapLatLimit',[-90 90],'MapLonLimit',[-90 90]); 
gridm 
plotm(0,0,'o','MarkerSize',18,'MarkerFaceColor','g');

I want to hide the grid lines behind the marker.

Answer 1

[Michael]

The grid lines appear in front of the marker as the default ‘ZData’ property of grid lines is positive. Set the ‘ZData’ values of grid lines to be negative.

axesm('pcarree','MapLatLimit',[-90 90],'MapLonLimit',[-90 90]);
Hg = gridm;
plotm(0,0,'o','markersize',18,'markerfacecolor','g');
set(Hg(1),'ZData',0*get(Hg(1),'ZData')-1);
set(Hg(2),'ZData',0*get(Hg(2),'ZData')-1);

[Walter Roberson]

Possibly true in practice, but see below for the more official mechanism.

Answer 2

[Walter Roberson]

axesm reference

GAltitude

    scalar z-axis value {Inf}
    Grid z-axis setting — Sets the z-axis location for the grid when displayed. Its default value is infinity, which is displayed above all other map objects. However, you can set this to some other value for stacking objects above the grid, if desired.

Thus in order to have the markers above the grid, the GAltitude must be set below the lowest altitude used in the map.