Opened 5 years ago

Closed 5 years ago

#31753 closed Bug (invalid)

SpatialReference srid -> proj4 -> srid returns wrong SRID

Reported by: Riccardo Owned by: nobody
Component: GIS Version: dev
Severity: Normal Keywords: SRID; SpatialReference; GDAL
Cc: Triage Stage: Unreviewed
Has patch: no Needs documentation: no
Needs tests: no Patch needs improvement: no
Easy pickings: no UI/UX: no

Description

A SpatialReference object with a specific SRID (e.g. 32630 - ​https://epsg.io/32630) can be instantiated and then transformed into a proj or proj4 string (method .proj/.proj4). If that string is then used to instantiate a new SpatialReference object, that object will have a different SRID, encoding a different type of projection (e.g. 6326 - ​https://epsg.io/6326).

For example:

>>> from django.contrib.gis.gdal import SpatialReference
>>> srid = 32630
>>> p4 = SpatialReference(srid).proj4
>>> new_sr = SpatialReference(p4)
>>> new_sr.srid == srid
False
>>>  new_sr.srid
6326

Change History (1)

comment:1 by Claude Paroz, 5 years ago

Resolution: → invalid
Status: new → closed

I'm afraid Django cannot do anything here, it is probably a GDAL "issue" (Django is simply getting the SetFromUserInput GDAL API result).
In any case, I would discourage using a Proj string to create a SpatialReference.

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