*Klaus Mithöfer*
/Tue Jun 28 06:54:55 PDT 2022/
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how the grid snapping work?
Hi Klaus,
the QgsMapToPixelSimplifier Class [1] gives a hint about what the
"Simplify" algorithm "Snap to grid" method do:
SnapToGrid
The simplification uses a grid (similar to ST_SnapToGrid) to remove
duplicate points.
The code used for the "Snap to grid" method is at [2].
Another algorithm that snaps the vertex to a grid is the "Snap points to
grid" [3], but this doesn't actually simplify the geometries, just
simplifies the coordinates of the geometries.
Regards.
Andrea Giudiceandrea
[1]
https://api.qgis.org/api/3.22/classQgsMapToPixelSimplifier.html#a0b97d82a3abd0876ce529ba9d9cfd412
[2]
https://github.com/qgis/QGIS/blob/e113457133fe5d7c3f5e3b90a2795b8b691ae269/src/core/qgsmaptopixelgeometrysimplifier.cpp#L183-L229
[3]
https://docs.qgis.org/3.22/en/docs/user_manual/processing_algs/qgis/vectorgeometry.html?highlight=simplify#snap-points-to-grid
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