Hi all I have used postgres 17.2 with postgis 3.5.1 POSTGIS="3.5.1 48ab069" [EXTENSION] PGSQL="170" GEOS="3.13.0-CAPI-1.19.0" PROJ="9.5.1 NETWORK_ENABLED=OFF URL_ENDPOINT=https://cdn.proj.org USER_WRITABLE_DIRECTORY=/var/lib/pgsql/.local/share/proj DATABASE_PATH=/usr/proj95/share/proj/proj.db" (compiled against PROJ 9.5.1) LIBXML="2.9.13" LIBJSON="0.14" LIBPROTOBUF="1.3.3" WAGYU="0.5.0 (Internal)" TOPOLOGY
As it should already fix the issue of loosing st_srid while doing st_union. However when doing : select ST_SRID(ST_GeomFromText('POLYGON ((4.9882543 50.4415584, 4.9882543 50.4415586, 4.9882545 50.4415586, 4.9882545 50.4415584, 4.9882543 50.4415584))',4326)), st_srid(ST_UNION(ARRAY[ST_GeomFromText('POLYGON ((4.9882543 50.4415584, 4.9882543 50.4415586, 4.9882545 50.4415586, 4.9882545 50.4415584, 4.9882543 50.4415584))',4326)])) ; again it is 4326 v 0. Can someone confirm that fix was released in 3.5.1 ? Best regards Łukasz Szałek