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<p>Please file an issue with a (as small as possible) .dxf file
reproducing the issue<br>
</p>
<p>Even<br>
</p>
<div class="moz-cite-prefix">Le 25/02/2024 à 22:05, Jan Heckman a
écrit :<br>
</div>
<blockquote type="cite"
cite="mid:CAKMUAtDMPDqYZQZ5u=HFA8geTfeJ_t7wtdzGOLya1wfa34ct4Q@mail.gmail.com">
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<div>Hi Even, all,</div>
<div>There might be a slight connection, but my case imo does
not involve either a bulgefactor or a smoothing routine;</div>
<div>it is the basic conversion/render of a circular arc where
apparently start- and endangle are interchanged sofar without
apparent cause.</div>
<div>Possibly the dxf has, earlier on, something which
influences (rightly or wrongly) the clockwise setting/bool
seen in this type of driver function.</div>
<div>So I'll first try to find any global setting in the dxf
which might encourage clockwise circle handling instead of
default anti-clockwise.</div>
<div>As an afterthought, this cannot be the case as then the arc
would have been drawn in the other direction, giving a very
large arc instead of a smallish one.</div>
<div>As I said earlier, the correct arc is used but with the
(imo) wrong orientation/sequence of the vertices.</div>
<div>Jan<br>
</div>
<div><br>
</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Sun, Feb 25, 2024 at
2:08 PM Even Rouault <<a
href="mailto:even.rouault@spatialys.com"
moz-do-not-send="true" class="moz-txt-link-freetext">even.rouault@spatialys.com</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote"
style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hi,<br>
<br>
I'm wondering if there woulnd't be a connection with <br>
<a
href="https://github.com/OSGeo/gdal/issues/1839#issuecomment-537185826"
rel="noreferrer" target="_blank" moz-do-not-send="true"
class="moz-txt-link-freetext">https://github.com/OSGeo/gdal/issues/1839#issuecomment-537185826</a>
?<br>
<br>
Even<br>
<br>
Le 25/02/2024 à 13:32, Jan Heckman via gdal-dev a écrit :<br>
> Hi all,<br>
> Sorry for a somewhat long post, but here we go:<br>
> I am converting a .dxf having a sequence of simple lines
and arcs <br>
> which form a continuous (poly)line, (correctly) ordered
by <br>
> EntityHandle. The arcs are converted (to shp) as well as
displayed <br>
> (Qgis) in the opposite direction as the simple lines.
Checking the <br>
> codes and docs, this appears wrong.<br>
> Below the minimal relevant information, I can add the
complete .dxf, <br>
> but I think attached files are frowned upon?<br>
><br>
> Docs cited:<br>
> <a
href="https://help.autodesk.com/view/OARX/2024/ENU/?guid=GUID-0B14D8F1-0EBA-44BF-9108-57D8CE614BC8"
rel="noreferrer" target="_blank" moz-do-not-send="true"
class="moz-txt-link-freetext">https://help.autodesk.com/view/OARX/2024/ENU/?guid=GUID-0B14D8F1-0EBA-44BF-9108-57D8CE614BC8</a><br>
> ARC (DXF)<br>
> The following group codes apply to arc entities.<br>
> Arc group codes<br>
> Group code Description<br>
> 100 Subclass marker (AcDbCircle)<br>
> 39 Thickness (optional; default = 0)<br>
> 10 Center point (in OCS) DXF: X value; APP: 3D point<br>
> 20, 30 DXF: Y and Z values of center point (in OCS)<br>
> 40 Radius<br>
> 100 Subclass marker (AcDbArc)<br>
> 50 Start angle<br>
> 51 End angle<br>
> 210 Extrusion direction (optional; default = 0, 0, 1)
DXF: X value; <br>
> APP: 3D vector<br>
> 220, 230 DXF: Y and Z values of extrusion direction
(optional)<br>
><br>
> <a
href="https://ezdxf.readthedocs.io/en/stable/tutorials/dxf_primitives.html"
rel="noreferrer" target="_blank" moz-do-not-send="true"
class="moz-txt-link-freetext">https://ezdxf.readthedocs.io/en/stable/tutorials/dxf_primitives.html</a><br>
> The arc goes always in counter-clockwise orientation
around the z-axis <br>
> more precisely the extrusion vector of OCS, but this is
beyond the <br>
> scope of this tutorial.<br>
><br>
> The case (extracted, whole .dxf file available):<br>
> AcDbEntity<br>
> 8<br>
> 0000-001_09_AND1N<br>
> 6<br>
> Continuous<br>
> 62<br>
> 18<br>
> 100<br>
> AcDbCircle<br>
> 10<br>
> 130974.661837<br>
> 20<br>
> 497502.478468<br>
> 30<br>
> 0.0<br>
> 40<br>
> 7576.094430000001<br>
> 100<br>
> AcDbArc<br>
> 50<br>
> 305.5444330000001<br>
> 51<br>
> 344.795475<br>
> 0<br>
> LINE<br>
> 5<br>
> 2E<br>
> 330<br>
> 1A0<br>
> 100<br>
><br>
> The arc is converted (.shp) and drawn (qgis) from end
angle to start <br>
> angle, without a 210 code to alter default behavior,
which obviously <br>
> is the other way around, noting counter clock around
(positive) Z-axis.<br>
> The applicability of this convention also follows from
the (correct) <br>
> position of the arc in the conversion and drawing.<br>
> Only begin- and endpoints are interchanged.<br>
><br>
> Please advice,<br>
> Thanks in advance,<br>
> Jan<br>
><br>
> _______________________________________________<br>
> gdal-dev mailing list<br>
> <a href="mailto:gdal-dev@lists.osgeo.org"
target="_blank" moz-do-not-send="true"
class="moz-txt-link-freetext">gdal-dev@lists.osgeo.org</a><br>
> <a
href="https://lists.osgeo.org/mailman/listinfo/gdal-dev"
rel="noreferrer" target="_blank" moz-do-not-send="true"
class="moz-txt-link-freetext">https://lists.osgeo.org/mailman/listinfo/gdal-dev</a><br>
<br>
-- <br>
<a href="http://www.spatialys.com" rel="noreferrer"
target="_blank" moz-do-not-send="true"
class="moz-txt-link-freetext">http://www.spatialys.com</a><br>
My software is free, but my time generally not.<br>
<br>
</blockquote>
</div>
</blockquote>
<pre class="moz-signature" cols="72">--
<a class="moz-txt-link-freetext" href="http://www.spatialys.com">http://www.spatialys.com</a>
My software is free, but my time generally not.</pre>
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