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How can I generate a line with given center point, angle and length in QGIS?

I am analyzing that auto extraction lineament for geologic structure analyze.

Taras
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kang6gab
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    y=mx+c should be all you need – Ian Turton Nov 08 '21 at 08:47
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1 Answers1

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Creating a line without PyQGIS, using only QGIS expressions: Use either Geometry generator (for visualization only) or create actual geomtries with Geometry by expression - use this one to create actual geometries (real lines): see here for details).

If the point should be in the middle of the line, simply extend the line. Use this expression for a line with length of 20 and angle (azimuth: angle clockwise from north) of 112° degrees:

extend (
    make_line(
        $geometry,
        project(
            $geometry,
            20,
            radians(112)
        )
    ),
    20,
    0
)

enter image description here

Babel
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  • Thanks for your reply. What I really want to know is create real lines (features). The method you taught me is just styling. And the position of the line is the center point of the point. Again, please answer my question. – kang6gab Nov 09 '21 at 09:38