Hypsographic Curve

[tcld]

While thinking about the values to choose for PR 188, I thought I might want to take a look at the elevation distribution of a world. So I added some code to generate a hypsographic curve of the world.

Data corresponding to this PR can be found here.

Example for the test-world (28070):

image removed because it was ugly
The y-axis shows the different heights (all heights are occupied!), x shows the percentage - exactly as in the link about the hypsographic curve I gave above.

A couple of things can be seen:

• oceans are kind of shallow in comparison to Earth
• the general shape of the curve seems ok (even though the land is a bit too high on average)
• there are some very high places in that world

It would probably be interesting to take a look at this plot right as the heightmap comes out of Platec. Aside from that I hope to finally find good values for PR 188 - if somebody can give hints, please do so.

EDIT: This also shows that we shouldn't just "fill up" the ocean to an arbitrary value after Platec generated the world making use of a very specific ocean-level. If the ocean_level variable is to be repaired, it should tie into Platecs generation.

EDIT2:
A slightly improved plot - there is a vertical line every ten percent now and a horizontal line for the different height thresholds (sea, plains, hills):

Here what it would look like after #188, the thresholds from bottom to top being sea, plains, hills, low mountains, medium mountains, high mountains:

[ftomassetti]

About the fact that ocean are shallow: we can easily rescale that

[ftomassetti]

I think this plot could be an interesting addition for the more technical users

[tcld]

I changed the code to make use of matplotlib. It is only one commit so far, so I could go back, if necessary.