[gis] Current locale considered when converting a geometry to WKT

[luizvital <luiz.vital@…>]

I'm getting a OGRGeometry Exception intermittently, when saving a form.

After debuging the code I noticed that the WKT string generated from
geometries were taking the current locale into account, thus raising
the Exceptions due to a bad WKT string representation. Here goes an
example:

>>> import locale
>>> from django.contrib.gis.geos import Point
>>> p = Point(-45.23, -23.15)
>>> p.wkt
'POINT (-45.2299999999999969 -23.1499999999999986)'
>>> locale.getlocale()
(None, None)
>>> locale.setlocale(locale.LC_ALL, ('pt_BR','UTF-8'))
'pt_BR.UTF8'
>>> p.wkt
'POINT (-45,2299999999999969 -23,1499999999999986)'

Notice de comma "," for decimal separator in the last output.

It must be something in the GEOS C library and in this case should be
fixed there, but maybe it should be avoided reseting de locale before
calling the C routine and restoring the locale to what it was just
after.

I think the reason this problem was not always happening is related to
the some setlocale thread safety issue.

I was using the wkt from the geometry in a custom form PointField to get the coordinate transformed to the desired srid.

[jbronn]

Confirmed. To add the locale on Ubuntu do: sudo locale-gen pt_BR.UTF-8.

[luizvital <luiz.vital@…>]

Well, I've got enough reasons not to use python locale.setlocale as per official docs point:

• ​http://docs.python.org/lib/module-locale.html
• ​http://docs.python.org/lib/node745.html "...it is generally a bad idea to call setlocale() in some library routine..."

But is still can be an issue to unattented users (like me), so I filed a ticket in the GEOS trac ​http://trac.osgeo.org/geos/ticket/201

[jbronn]

Because this is an underlying bug in GEOS I'm closing this ticket. Thanks to Luiz for filing a ticket with the GEOS folks (​#201).