On 22/03/15 21:37, Markus Neteler wrote:
On Sun, Jan 11, 2015 at 9:03 PM, Markus Metz
<[email protected]> wrote:
On Fri, Jan 9, 2015 at 9:35 AM, Moritz Lennert wrote:
On 08/01/15 23:46, Markus Metz wrote:
On Mon, Jan 5, 2015 at 12:17 PM, Benjamin Ducke wrote:
Thanks Markus, this is excellent progress.
It seems to me that the approximation of cluster shapes from grouped
points is a generic problem that would best be solved with a separate
module. As long as the shapes are roughly convex, the existing v.hull
should work fine. For concave shapes, AFAIK things become messy because
common methods such as alpha shapes require the user to provide
threshold values.
This is true, but v.concave.hull [0] could help ;-)
All these great addons !
For this particular one: would it be interesting / possible to integrate it
directly into v.hull ?
No, because v.hull is a C module and v.concave.hull a script which
does not use v.hull at all. Instead, v.concave.hull cleans the output
of v.delaunay to create concave hulls.
I have a similar problem: imagine a set of contour lines which
describe the bathymetry of a lake, so essentially contour lines which
are closing a polygon but consist of different lines.
I'm not sure I completely understand the situation, maybe an image would
help.
I would like to get the respective polygon representation, i.e. the
outer lines only and those turned into a polygon.
I just tried v.concave.hull on it, however, it expects points and not lines.
Does anyone have an idea how to achieve that?
I take it that there are no attributes (e.g. depth) linked to the lines ?
Otherwise, maybe v.to.points + v.concave.hull + v.select ?
Or, manually, using the new "Select vector feature(s)" tool in the Map
Display ?
Moritz
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