How to make land surface black using ETOPO data

Hi All,

I'm trying to create an map using ETOPO data that shows ocean bathymetry, but blacks out anything above sea level (i.e., land). For example, the region around New Zealand. I want NZ to be entirely black, and Z to be o (sea level) to the sea floor.

So far, I can only make the land boundaries black using geoshow, but not the entire land surface.

Any ideas?

Answer 1

[Carl]

Hi Vincent. You can try setting the axes "CLim" property, and using a custom colormap. This will let you set everything above a certain Z value (elevation) to be some color (black). For example:

% After plotting your data with geoshow
clim = get(gca,'CLim');
clim(2) = 0;
set(gca,'CLim',clim)
newmap = colormap;
newmap(end,:) = [0 0 0];
colormap(newmap)

See the documentation below for more on the "CLim" property:

http://www.mathworks.com/help/matlab/ref/axes-properties.html?s_tid=srchtitle#property_d0e55435

and using colormaps:

https://www.mathworks.com/help/matlab/ref/colormap.html