[Qgis-user] Polar stereographic (0 - 360 longitudes)

[Brent Wood]

I don't believe you can.

The underlying proj libraries (as used by QGIS) no longer support longitudes > 180 by default, so any re-projection from EPSG:4326 will only work with +-180 longitudes.

There isa command line parameter (+over) which can be used with proj on the command line but I don't think this is supported by QGIS.

If you use Postgis (or Spatialite), there is an ST_ShiftLongitude() function that will switch +-180 to 0-360 or the reverse which makes the operation pretty trivial for any sort of geometry.

I have created a custom QGIS/Postgis projection (many years ago) which I assigned a code of 4327, this was essentially 4326 in a 0-360 degree space, so I could reproject between them, I'm not sure if this is still possible with the latest versions of proj with wkt definitions.

Brent Wood

Principal Technician, Fisheries
NIWA
DDI:  +64 (4) 3860529

________________________________
From: Qgis-user <qgis-user-bounces at lists.osgeo.org> on behalf of Lester Anderson via Qgis-user <qgis-user at lists.osgeo.org>
Sent: Sunday, June 19, 2022 22:16
To: qgis-user at lists.osgeo.org <qgis-user at lists.osgeo.org>
Subject: [Qgis-user] Polar stereographic (0 - 360 longitudes)

Hi all,

I have data which is in 0-360 degree longitudes and I would like to apply a Polar stereographic projection. However, since the EPSG 3995 has limits of -180/+180 for longitude, as expected it gives half the plot.

For some reason I cannot create a custom projection with an extent such as:
xmin=0, xmax=360, ymin=60, ymax=90 based on 3995 even removing reference to this ID.

Any ideas how to proceed without having to shift it all to +/- 180

Tested in 3.20 and 3.24

Thanks

Lester
[https://www.niwa.co.nz/static/niwa-2018-horizontal-180.png] <https://www.niwa.co.nz>
Brent Wood
Principal Technician - GIS and Spatial Data Management
Programme Leader - Environmental Information Delivery
+64-4-386-0529

National Institute of Water & Atmospheric Research Ltd (NIWA)
301 Evans Bay Parade Hataitai Wellington New Zealand
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