I think that this could also be done as post-processing step: collapsing
lines that are really close-by a discontinuity on the discontinuity (snap).
I was thinking about using the borders I introduced to close contours
(no data zones and raster edges) to handle those discontinuities, but I
don't t
In cases of cliffs and such (i.e. sudden drops in altitude), traditional
photogrammetric softwares like PCI and Erdas work with break lines, as in,
you literally draw a line along edges you want computed discontinuously.
That is not really practical to do in command-line GDAL, though you could
impo
Le 20/10/2017 à 20:18, Andrew C Aitchison a écrit :
> On Fri, 20 Oct 2017, Vincent Mora wrote:
>
>> I'll also try the gdal_polygonize approach, but I don't think it's the
>> same thingl: with raster-classif + gdal_polygonize, if you have 3
>> classes 1,2,3 polygons from 1 can touch a polygon from
On Fri, 20 Oct 2017, Vincent Mora wrote:
I'll also try the gdal_polygonize approach, but I don't think it's the
same thingl: with raster-classif + gdal_polygonize, if you have 3
classes 1,2,3 polygons from 1 can touch a polygon from 3, with contour
lines there will always be a polygon of class 2
Hi all,
Thanks a lot for the feedback.
I have also resorted to polygonize (geos-polygonize) and ran into the
classification problem that you mention. There is also the issue of
performance if you have a lot of complex polygons, on a high res raster,
contours would take a couple of seconds, and ge
> I think I did something similar to the "ends matching" in a python
> script that creates those polygons (in a particular context that also
> requires tiling).
>
> What I'd like to know, is if there is a reason why it's not already
> available in gdal, since there is the need for that and apparent
I too have run into this problem in the past, though I believe, if you are
to use gdal_contour you have access to the underlying DEM/TIN/LAS, and if
you have that it's much easier just converting it directly to polygons
(using the technique Jamie posted, or similar ones). It could be a
gdal_contour
>From a user perspective, this can be done pretty easily using gdal_calc.py
& gdal_polygonize.py. I've used this technique in the past several times.
This doesn't help with gdal_contour of course, but is a viable way of doing
the same thing. Maybe worth considering as a new python tool.
Using a ra
Hi Gregers,
Thanks for your reply.
The question was not "how to" yet, but "shall I" ;o)
I think I did something similar to the "ends matching" in a python
script that creates those polygons (in a particular context that also
requires tiling).
What I'd like to know, is if there is a reason why i
On jeudi 19 octobre 2017 14:11:45 CEST Vincent Mora wrote:
> Hi all,
>
> I know this is old stuff (references below), but making polygons instead
> of lines would be a great option for gdal_contour IMO.
>
> It could be also another program included in gdal/app (if it is already,
> I can't find it
Hi Vincent,
> I know this is old stuff (references below), but making polygons instead
> of lines would be a great option for gdal_contour IMO.
>
> It could be also another program included in gdal/app (if it is already,
> I can't find it).
>
> What do you think, shall I add that ? If yes, first o
Hi all,
I know this is old stuff (references below), but making polygons instead
of lines would be a great option for gdal_contour IMO.
It could be also another program included in gdal/app (if it is already,
I can't find it).
What do you think, shall I add that ? If yes, first or second option
On Wed, 2008-09-03 at 10:40 +0300, Ari Jolma wrote:
> > Indirectly, yes. You can use r.reclass to create areas of similar
> > elevation from the raster DEM and r.to.vect to covert to polygons.
Also, use the "-s" switch (in r.to.vect) to get smoothed and not edgy
polygons :-)
_
Matthew Perry kirjoitti:
On Tue, Sep 2, 2008 at 2:26 PM, Ari Jolma <[EMAIL PROTECTED]> wrote:
Did you ever want gdal_contour to produce polygons instead of lines?
...
I wonder what's the current situation. Does GRASS do this?
Indirectly, yes. You can use r.reclass to create
On Tue, Sep 2, 2008 at 2:26 PM, Ari Jolma <[EMAIL PROTECTED]> wrote:
> Did you ever want gdal_contour to produce polygons instead of lines?
...
> I wonder what's the current situation. Does GRASS do this?
>
Indirectly, yes. You can use r.reclass to create areas of similar
elevation from the raster
Did you ever want gdal_contour to produce polygons instead of lines?
I made a small Perl program that uses the Perl bindings to GDAL and
which converts the lines into polygons. The polygons represent "plates"
of equal elevation and thus overlap. The polygons are stored into a new
layer in such
16 matches
Mail list logo
