Timeline for How to get a bounding box in one SRID of a bounding box in another SRID?
Current License: CC BY-SA 4.0
8 events
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| Dec 18, 2023 at 16:05 | comment | added | geozelot | This question and comments feel like a balance act between might work by accident and the abyss of misconception ,) | |
| Dec 12, 2023 at 18:57 | comment | added | Him | @dr_jts ah, I see that you're correct. I was incorrectly assuming that 4326 segmentations and boxes would be along great circles, because 4326 is a "3D projection". Apparently this isn't the case, and the 3857 bbox and the 4326 bbox are identical in postGIS. | |
| Dec 12, 2023 at 18:41 | comment | added | dr_jts |
If the object is a geometry (which a polygon in 3847 is) then ST_Segmentize adds vertices along the straight-line segments, as required.
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| Dec 12, 2023 at 16:40 | comment | added | Him |
ST_Segmentize doesn't actually work here, because it densifies the box along a great circle arc, and not in the original projection. So, when I densify my 3857 bbox, the polygon is no longer a "box" in 3857.... From the docs: "Added vertices are created along the spherical great-circle arcs defined by segment endpoints."
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| Dec 12, 2023 at 16:27 | comment | added | Babel | If you succeed, post it as an answer so it can help others. | |
| Dec 12, 2023 at 16:07 | comment | added | Him |
@Babel I think so, yes. So, I think you're proposing a process that would be to ST_MakeEnvelope in 3857, then ST_Segmentize the result to an appropriate density, then ST_Transform that to 4326, then ST_Extent the result. I will try to put this workflow together and get back to this thread.
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| Dec 12, 2023 at 16:00 | comment | added | Babel | Not exactly sure what your goal is, but would densifying the bounding box, then reprojecting help? See gis.stackexchange.com/a/392248/88814 | |
| Dec 12, 2023 at 15:54 | history | asked | Him | CC BY-SA 4.0 |