[Qgis-developer] closestSegmentWithContext

[Worth Lutz]

Thanks for that link.  That's the direction I'm headed.

I posted here to find out if this is an error in the python 
implementation or documentation and see if I should submit an issue.

*Worth Lutz*


On 5/6/2016 8:15 AM, Caio Hamamura wrote:
> I've already used this function and it returned exactly the same you 
> claim to receive. But you can calculate the position yourself, it is 
> actually simple. Check it out:
>
> http://stackoverflow.com/a/1560510/2548351
>
>
>
> 2016-05-05 13:25 GMT-03:00 Worth Lutz <wal3 at mindspring.com 
> <mailto:wal3 at mindspring.com>>:
>
>     I'm trying to use "closestSegmentWithContext" method of
>     QgsGeometry in a plugin. I don't seem to be getting what I'm
>     expecting.
>
>     Comparing
>     http://qgis.org/api/classQgsGeometry.html#ac09505a6a8a29f244a37c6f336cd98e7
>
>     with the following from:
>     https://github.com/qgis/QGIS/blob/master/python/core/geometry/qgsgeometry.sip
>
>         /**
>          * Searches for the closest segment of geometry to the given point
>          * @param point Specifies the point for search
>          * @param minDistPoint Receives the nearest point on the segment
>          * @param afterVertex Receives index of the vertex after the
>     closest segment. The vertex
>          * before the closest segment is always afterVertex - 1
>          * @param leftOf Out: Returns if the point lies on the left of
>     right side of the segment ( < 0 means left, > 0 means right )
>          * @param epsilon epsilon for segment snapping (added in 1.8)
>          * @return The squared cartesian distance is also returned in
>     sqrDist, negative number on error
>          */
>         double closestSegmentWithContext( const QgsPoint& point,
>     QgsPoint& minDistPoint /Out/, int& afterVertex /Out/ ) const;
>
>
>     When I try:
>
>         results =
>         self.selectedStreetSegment.geometry().closestSegmentWithContext(point)
>
>
>     I get a results as:
>
>         (2560.365846544, (2106395, 746610), 1)
>
>     I take this to be (sqrDist, minDistPoint, afterVertex ). It does
>     not seem to be returning "leftOf" which is the value I'm looking for.
>
>     Is something missing in that "sip" definition?  I do not know what
>     I'm looking at so I may be looking at the wrong thing. In any
>     case, I cannot seem to find the results I need.
>
>     Thanks,
>     --
>     *Worth Lutz*
>
>
>
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