Earth height-maps, with adjustable sea/fog level

Question

I like the Eleven Pillars idea, hinted at the linked post, and I would like to adapt it to out Earth. In order to do that, I'd need something like a heightmap, with adjustable sea level, to simulate the fog itself. It would be even better if it allowed me to raise or lower the sea level in different zones, but that's not a requirement.

If there isn't one with all these features, then even a simple heightmap would suffice, I might code the sea-level adjusting myself, somehow.

Since the aim and the inspirations are both RPG I posted here, but if you think there was a more appropriate SE for this specific task, this could be moved.

Answer 1

You can find lots of height maps of earth if you Google image "earth height map". If you take one of these and bring it into an image editor, even MS Paint, you can flood-fill with a new color to block out over and under fog locations.

http://www.dampes8n.com/heightmap.png

Specifically, the above image was made in photoshop by me with these steps:

1. found height map
2. duplicated the map on a new layer
3. flood-filled with the paintbucket set to a tolerance of 60 and not contiguous on a lower section of land (actually, the east-most tip of greenland)
4. selected that filled section with the magic wand
5. cutting it out of the duplicate layer and pasting it on a new layer
6. delete the duplicated layer
7. set the new fog shape layer to 'multiply' so it pulled the gradient of the map below it into the purple color.
8. ????
9. profit

Answer 2

One can use Fractal Terrains Pro or to import the GIS data, and then adjust sea level as desired. This also allows adding some additional topographic changes if desired.