[Qgis-user] Results from QgsGeometryUtils.lineCircleIntersection

[Zoltan]

Hi,
I am struggling with using QgsGeometryUtils.lineCircleIntersection in a 
python script I am writing outside of QGIS 3.20.3 [495fbaec], using PyCharm.
In 
https://qgis.org/pyqgis/3.2/core/Geometry/QgsGeometryUtils.html#qgis.core.QgsGeometryUtils.lineCircleIntersection
it says that:    If the intersection has two solutions (points), the 
closest point to the initial intersection point is returned.

I am wanting to find the coordinate on the polyline, that is at a set 
distance from the polyline startpoint.
Note that this polyline meanders so I cannot do this using point on line 
at distance 'd' from startpoint

Unfortunately this utility extends my vertex to vertex line segments and 
I get results where the intersection point is not actually ON my 
line-segment.
This is easy to check for, but the problem is that this utility only 
returns the first intersection point found, which is not always the one 
actually sitting on my line-segment.

Am I approaching this problem incorrectly, or is this a known 'feature' 
of this utility?

Any guidance welcome.

Thanks and regards,
Zoltan


-- 

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Zoltan Szecsei GPrGISc 0031
Geograph (Pty) Ltd.
GIS and Photogrammetric Services

Cape Town, South Africa.

Mobile: +27-83-6004028 (Signal, not WhatsApp)
www.geograph.co.za
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