New answers tagged postgis
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PostGIS: Correct way of using ST_Union/ST_Difference with or without gridsize
I found some algorithms to remove the spikes that can be seen in the question, and for provided example it worked, but for more complex examples still st_touches is not working. I will leave the links,...
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Accepted
PostGIS: Correct way of using ST_Union/ST_Difference with or without gridsize
Using a grid size argument in the overlay functions is a good way to avoid the spikes that you are seeing in the full-precision results.
ST_Touches is a very specific spatial situation. It would be ...
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ST_DWithin rows underestimated
You placed all 2000 of your generated points on a diagonal line running in 0.0005° steps North-East, the furthest one sitting 1° or 131_198 meters away. Only 16% of your points stick out the 110_000 ...
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Point within polygon in a certain distance of "point on surface"
You can draw a circle around your point, take its intersection with the polygon and ask for a point on that - ST_PointOnSurface() works fine on lines:
demo at db<>fiddle
select ...
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PostGIS data with serial id doesn't automatically calc a proper id when adding new geometry
found a way: thanks to Auto-increment id when adding a feature to a PostGIS layer in QGIS where using the data type BIGSERIAL is suggested in this way: ALTER TABLE your_table ADD COLUMN idcolumn ...
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Combining (merging) neighbour points to one centred point in PostGIS (reducing density)?
You could implement grid-based clustering with representative points. It's described in this answer: https://gis.stackexchange.com/a/352703/14766
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