[postgis-users] Failing ST_Transform with Ross Ice Shelf polygon

[Paul Ramsey]

> On Nov 6, 2023, at 3:33 PM, Marco Boeringa <marco at boeringa.demon.nl> wrote:
> 
> Well, yes indeed that is what is happening, 180 came out of the reprojection steps as -180. Full output geometry below. Is there any way to prevent this behavior?
> 
> Marco
> 

Not really… Either snap to grid or reduce precision

https://postgis.net/docs/ST_ReducePrecision.html
https://postgis.net/docs/ST_SnapToGrid.html

will get you back onto the dividing line (note that it is at -180.00000000000014), but that won’t help in flipping -180 to 180. For your particular case, applying

https://postgis.net/docs/ST_ShiftLongitude.html

will fix it, I think, though not in generality

P
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