#34302: SpatialReference.srid incorrectly assumes first AUTHORITY value to be
projection SRID
------------------------------+----------------------------------------
Reporter: Stefan Brand | Owner: Stefan Brand
Type: Bug | Status: assigned
Component: GIS | Version: dev
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
------------------------------+----------------------------------------
Changes (by Stefan Brand):
* owner: nobody => Stefan Brand
* status: new => assigned
Comment:
While applying the change, I got a failing test. It turns out that
GeoDjango has a different behaviour than the GDAL Python bindings.
Compare:
{{{
#!python
from django.contrib.gis.gdal import SpatialReference
from osgeo import ogr
WEB_MERCATOR = """PROJCS["WGS 84 / Pseudo-Mercator",
GEOGCS["WGS 84",
DATUM["WGS_1984",
SPHEROID["WGS 84",6378137,298.257223563,
AUTHORITY["EPSG","7030"]],
AUTHORITY["EPSG","6326"]],
PRIMEM["Greenwich",0,
AUTHORITY["EPSG","8901"]],
UNIT["degree",0.0174532925199433,
AUTHORITY["EPSG","9122"]],
AUTHORITY["EPSG","4326"]],
PROJECTION["Mercator_1SP"],
PARAMETER["central_meridian",0],
PARAMETER["scale_factor",1],
PARAMETER["false_easting",0],
PARAMETER["false_northing",0],
UNIT["metre",1,
AUTHORITY["EPSG","9001"]],
AXIS["Easting",EAST],
AXIS["Northing",NORTH],
EXTENSION["PROJ4","+proj=merc +a=6378137 +b=6378137 +lat_ts=0 +lon_0=0
+x_0=0 +y_0=0 +k=1 +units=m +nadgrids=@null +wktext +no_defs"],
AUTHORITY["EPSG","3857"]]"""
geodjango_srs = SpatialReference(WEB_MERCATOR)
geodjango_srs.validate() # raises for invalid SRS
print(geodjango_srs.attr_value("AUTHORITY", 1))
print(geodjango_srs.auth_code(target=None))
ogr_srs = ogr.osr.SpatialReference(WEB_MERCATOR)
if ogr_srs.Validate(): raise
print(ogr_srs.GetAttrValue("AUTHORITY", 1))
print(ogr_srs.GetAuthorityCode(None))
}}}
> 3857
> None
> 3857
> 3857
The reason is that
[https://github.com/django/django/blob/fd21f82aa82b0d75a161f618ef944ebe0923e0ab/django/utils/encoding.py#L91-L108
`django/utils/force_bytes`] turns `None` into the byte string `b'None'`.
Since `ctypes.c_char_p` also accepts `None`, we can bypass `force_bytes`
if `target is None`.
I will do some more testing and push a patch tomorrow.
--
Ticket URL: <https://code.djangoproject.com/ticket/34302#comment:3>
Django <https://code.djangoproject.com/>
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