continental relief in png output

[Pablo Romero]

does anyone have any recipes/techniques for creating map plots with 3D continental relief/topographic features?

I've seen some other plots created with grads that appear to have land areas with detailed 3D terrain visible.
Im not sure how these are created; are they being 'printim'ed with a foreground png image? if so, how would I go about getting this 3D topographic image data?

P.Romero
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