[GRASS-dev] New directional buffering module or modified v.buffer

[Trevor Wiens]

On Wed, 14 Mar 2007 22:30:13 +0100
Maciej Sieczka wrote:

--- snip ---

> and let us know if the resulting buffers are OK? Most folks who tried
> it (actually, everyone who reported, besides Hamish) confirmed the
> output of v.buffer was bad. If v.buffer.ellipsoid has this problem
> fixed, it would be great news and I'd say that it should replace
> v.buffer then, if possible.

Well, it reproduces probably the same error that others are seeing.
After fiddling with this code for a couple of days I think I can
identify where the problems are, but will have to invest some time in
thinking about how to solve it. 

My quick assessment is as follows. On the west side, the bump is a
function of creating a semicircle to round the corner because there is
a new line segment. Unfortunately because there was no change in
direction, this semi-circle should not have been created.

On the south, the opposite direction is a function of angle of the line
being misread as to which is the inside and the outside. The north end
problem is the same problem.

Well, I guess I need to solve these problems before committing changes
to v.buffer. I take it that the general feeling is that enhancing
v.buffer is better than adding another module.

This may take a few days. I'll keep you posted.

T
-- 
Trevor Wiens 
twiens at interbaun.com

The significant problems that we face cannot be solved at the same 
level of thinking we were at when we created them. 
(Albert Einstein)