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that's a very interesting option ! I think i could write a tool in C++
to do the grouping, and use the original line strings for the elevation
lines/text.<br>
<br>
thanks a lot<br>
<br>
<br>
On 12/03/09 17:26, Jamie Adams wrote:
<blockquote
cite="mid:f4339510903120926s3ae849edo769d27ca835f5894@mail.gmail.com"
type="cite">You could also try using <a moz-do-not-send="true"
href="http://www.gdal.org/gdal_polygonize.html">gdal_polygonize</a>,
but you'd need to find a way to reclass your source raster to discrete
groups (i.e, elevation ranges). This could be done pretty easily using
python, maybe something like <a moz-do-not-send="true"
href="https://svn.osgeo.org/gdal/trunk/gdal/swig/python/samples/val_repl.py">val_repl.py</a>.
<br>
<br>
-Jamie<br>
<br>
<div class="gmail_quote">On Wed, Mar 11, 2009 at 12:56 PM, ValiSystem
<span dir="ltr"><<a moz-do-not-send="true"
href="mailto:vali.system@free.fr">vali.system@free.fr</a>></span>
wrote:<br>
<blockquote class="gmail_quote"
style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Hello
!<br>
<br>
I'm trying to generate polygons from gdal contour output. Most of the
linestrings generated where closed, so it's not a too bad start. The
problem is to define interior and exterior of the polygon : it seems
that interior and exterior has no consistent meaning from the
linestrings (it makes sense though - a line has no interior nor than
exterior).<br>
<br>
So what i need would be a method to recreate the meaning of the polygon
: the inside is where i have ground. To make it work, i just would have
to transform the polygon to an interior ring of a wider (whole area)
polygon when appropriate (when it does not contain a polygon with a
higher altitude).<br>
<br>
What do you think about this ? is there a better/known way to achieve
that ?<br>
<br>
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