Re: [Algorithms] Tangential Curvature of terrain

[Thatcher U. <tu...@tu...>]

From: Ron Levine <ro...@do...>

> Klaus Hartmann  wrote:
>
> >Again, I've reached a point, where I wished that my math skills were
better.
> >At least I hope that the answer to my question is not too easy, so that
> >maybe some math guys are interested. I cannot even promise that I'll be
able
> >to follow your replies, but I'm sure someday I will (after re-reading,
> >re-re-reading, ... :)
> >
>
> See your calculus book for the notion of "concave up" vs "concave
> down" as applied to the graph of a function.  I would take issue with
> Ulrich's use of the term "convex" where I use "concave down", because
> it corresponds poorly with other important connotations in the usual
> meaning of the term "convex".

Fair enough, I abused the calculus terms.  In the context of a heightfield
for GIS though, "concave up" and "concave down" are less intuitive than
"concave" and "convex" in the geometric sense, since we're talking about a
solid (the earth) with a well defined inside and outside.

> [snip]

Thanks for the interesting curvature stuff.

--
Thatcher Ulrich
http://tulrich.com